Defaults to 0. current/position_jitter. ggplot(df,aes(x=block,y=acc)) + geom_jitter(position=position_jitter(0. 3,2. Come on a journey through pull request #2196. Warning: position_dodge requires non-overlapping x intervals We can add individual points and lines onto this plot in a similar way, except you need to use a 2. The problem with the scale is that you're treating x as a factor, therefore, there is no notion of distance in it. If current interval is longer than a previous one then move current. Is this in line with what you are looking for? This specifies that strip. 6300000 0. The statistical transformation to use on the data for this layer, either as a ggproto Geom subclass or as a string naming the stat stripped of the stat_ prefix. 1. outlier. [1] "Converting non-logical columns to binary: Action, Animation, Comedy, Drama, Documentary, Romance, Short" [1] "Dropping empty groups: Short" Warning: position_dodge requires non-overlapping x intervals. Unlike position_dodge() , position_dodge2() works without a grouping variable in a layer. 3 2 10. A function can be created from a formula (e. Suppress message from geom_line with only one point. position_dodge() requires the grouping variable to be be specified in the global or. ply) : position_dodge requires non-overlapping x intervals. I shamelessly adapted ideas from both threads below, to which this question is a near-duplicate. We go along the array. And graph in plot: andresrcs December 2, 2019, 2:49am #9. Set the legend breaks to change the order of the keys without affecting the stacking. If any three intervals overlap with each other then there is no way to add any value of X to form Non-overlapping. We find leaf 8 with S3. end, b. 83756973 a A 2 0. asked Jul 6, 2022 in Programming Languages by praveen (62. ) intervals = [ [100,200], [150,250], [300,400]] intervalsSorted = sorted (intervals, key=lambda x: x [0]) # sort by start time for. Seems like it might be a bug? The dodging. Is there a way to adjust this at all? Some code:Dodge overlapping objects side-to-side Description. Is there a way of grouping my bars by activity, displaying them adjacently and varying their widths? Here's a bit of the df I'm using: Description. time complexity of O (nlogn), Where n is the size of the intervals. All categories; Programming Languages (694) Machine Learning (31) Operating Systems (114) Databases (91) Web & Google (85)Dodging preserves the vertical position of an geom while adjusting the horizontal position. Create non-overlapping stacked area plot with ggplot2 I have some data scraped and processed from the web in this form: I'm trying to created a stacked area chart, similar to the one here: Making a sta. position_dodge2()</code> works with bars and rectangles, but is particulary. For the interval arr [2], both arr [1] and arr [2] are on its right side and does not overlap with. I get a position_dodge () requires non-overlapping x intervals` warning with the following data and code. 13. 3, 0. Find centralized, trusted content and collaborate around the technologies you use most. Viewed 454 times. It is therefore discouraged to use these position adjustments in combination with scale transformations, such as logarithmic or square root scales. jitterdodge. Date, as. My solution for your problem is to: Divide data into overlapping and non-overlapping points. I would like for this to be a single point to avoid confusion, but still dodge the followup points. Warning message: "position_dodge requires non-overlapping x intervals" Since the variable colsample_bytree takes 3 discrete values and the variable alpha takes 6 I would expect to see 3 groups of boxplots --each group comprised from 6 boxplots corresponding to the different alpa values and each group positioned at a different value. 3,12. Date. Thanks in advance. Can you solve this real interview question? Non-overlapping Intervals - Given an array of intervals intervals where intervals[i] = [starti, endi], return the minimum number of intervals you need to remove to make the rest of the intervals non-overlapping. Markdown is a simple formatting syntax for authoring HTML, PDF, and MS Word documents. Inputs for plotting long-form data. This will change the stacking order, and the order of keys in the legend. I). 4. I will eventually overlay a mean crossbar and raw data points, but the main sticking point is creating a custom "box". They can be used by themselves as scatterplots or in combination with other geoms, for example, for labeling points or for annotating the height of bars. Dodging preserves the vertical position of an geom while adjusting the horizontal position. The raw data of parameter estimates for the different parameter settings is tidied into a tibble containing the data we need for both the DNA and complete phylogeny. position_stack requires non-overlapping x intervals; position_fill requires non-overlapping x intervals; position_dodge requires non-overlapping x intervals; position_dodge2 requires non-overlapping x intervals ，如果您的x变量应该针对不同的美学效果（例如填充）重叠，则可以尝试将x_var变成一个因子： geom_bar. To get what I think you want, you need to supply a suitable value to position_dodge (). The performance analysis uses the DAISIEprep. Default is ``0. . rm = TRUE) のエラー : KNN分類では 'x' は数値でなければならないWe then generate a random sample of tip states for each species, with the possible states being: endemic to the island, non-endemic and not present on the island. A function can be created from a formula (e. params = {"vjust": vjust, "reverse": reverse} def setup_params(self, data. ci_glm<- dput (head (ci_glm)) structure. Warning message: position_dodge requires non-overlapping x intervals. Defaults to 40% of the resolution of the data. I have a data frame with three continuous variables (x,y,z). x轴大小都在-100~100之间，y轴我分面都使用各自的范围，为什么还会出现这个？我该怎么修改,经管之家(原人大经济论坛). Warning: Ignoring unknown aesthetics: width Warning message: position_stack requires non-overlapping x intervals Any helps on make bar plot stacked or ideas on different plot type that can cover similar concepts would be highly appreciated. You can do quite a bit better: At first, accept the vector by value – this creates a copy right on the start: vector<Interval> Solution::merge (vector<Interval> data) // (note the dropped ampersand!) Then you can merge the intervals within this copy in place!I would like to create a boxplot-like graph in ggplot, except that the height of the boxes reflects 95% confidence intervals around the mean. When passing missing values to ggplot, it's very kind, and warns us that they are present. 0 on the grounds of full support for horizontality in ggplot. The more detailed meaning of the width parameter: Bar width. Half a violin plot is actually a classic density plot, just vertical. In this case, it was not necessary to change the boxes width. I've tried changing ggplot's aes width, I tried setting position="dodge", and a bunch of other things. 1600000 PE A Activity 0. Parameters: dataDataFrame, Series, dict, array, or list of arrays. r, R/geom-linerange. First plot runs, 2nd and 3rd plots (really same, called differently) both fail to produce 2-month boxplots for pre 2017 and one-month boxplots for 2017, as the grouper intends. position_dodge2(). height. 3,2. jitter_height : float Proportion to jitter in vertical direction. Unlike ggplot2::position_dodge(), position_dodgejust() attempts. outlier. 125, 3, by= 0. Course: Machine Learning: Master the Fundamentals by Stanford; Specialization: Data Science by Johns Hopkins University; Specialization: Python for Everybody by University of Michigan; Courses: Build Skills for a Top Job in any Industry by Coursera; Specialization: Master Machine. max = max(x. position_dodge() requires the grouping variable to be be specified in the global or geom_* layer. To reverse dodged element positions in position_jitterdodge(), it is necessary to use a negative value to dodge. 9), stat = "identity") + geom_errorbar ( position = position_dodge (width=0. Note that if max(a,c) > min(b,d), then the intervals do not overlap. Thus, ggplot2 will by default try to guess which orientation the layer should have. 5)) ). I'm afraid I need to see the overlap, so can't use facet. degree of jitter in x direction. A function can be created from a formula (e. Just one minor change solves the issue. 1)) # Plot y. width = 0. Asking for help, clarification, or responding to other answers. And I use the. The values for each parameter are overlapping and I would like to have the values for each x value (parameter) side by side. 0 for react=x≥16 in blue; Such that the desired output should look like. ## Warning: position_stack requires non-overlapping x intervals ## Warning: position_stack requires non-overlapping x intervals Well shucks, that looks like some kind of Atari graphics airplane. Orientation. cannot increase the normal width parameter too much when using position_dodge as it will push the bars into the other x-intervals, which is the reason for the warning message. It's not a problem though, as it plots perfectly well R ggplot2 position_dodge()` requires non-overlapping x intervals warning我收到了以下数据和代码的警告:position_dodge() Requires Non-Overlance x Intervals‘. A function can be created from a formula (e. However, this now gives me a warning: position_dodge requires non-overlapping x intervals. width=-. 343501e+13 ANO0006 500 901 1326 343750 7081250 6 5 ## 3 3 751 2. position 参数的作用是通过调用位置调整函数来调整图形要素的实际位置. Dodging preserves the vertical position of an geom while adjusting the horizontal position. Reload to refresh your session. The graphs in the previous section knit just fine, even though they use almost identical code, including geom_col and position_dodge in the geom_text section. Supressing Warnings in scale_x_datetime. position_dodge() position_dodge2() Dodge overlapping objects side-to-side position_identity() Don't adjust position. The key difference from all the examples I can find is that the x-axis should be bins of distance, but the y-axis the sum of tonne. position: Position adjustment, either as a string, or the result of a call to a position adjustment function. . stat: The statistical transformation to use on the data for this layer, as a string. This can be done in a number of ways, as described on this page. R","path":"R/geom-beeswarm. startHour = intervals[0][0] endHour = intervals[0][1] for interval in intervals[1:]: # if there is an overlap if interval[0] <= endHour <= interval[1]: endHour = interval[1] # if. If it is less than some threshold, then that point is overlapping with some point and so some zitter should be applied, while plotting that point. Source: R/geom-crossbar. height: degree of jitter in y direction. Vertical intervals: lines, crossbars & errorbars. How to make variable bar widths in ggplot2 not overlap or gap and. stat: The statistical transformation to use on the data for this layer, as a string. 5 Answers. 114501e+13 ANO0007 500 443 146 114750 6491250 7 5 ## OvervÃ. You can see. Therefore, we have created this dedicated raincloudplots package. November 19, 2020, 7:34pm #6. g. ggcoef_compare (): designed for displaying several models on. [docs] class position_stack(position): """ Stack plotted objects on top of each other The objects to stack are those that have an overlapping x range. I think the issue is due to position_dodge (). 3 小提琴图与箱型图同时展示 本文翻译自“TheWarning: `position_dodge()` requires non-overlapping x intervals `position_dodge()` requires non-overlapping x intervals. Part of R Language Collective. The task is to count the number of available non-overlapping intervals which need to be inserted in the arrays such that on merging the individual ranges in the arrays start[] and end[], the. Intervals represent physical entities. In other words, the output should be an array of mutually exclusive intervals. geom-bar. I want no space between bar 1 and bar2 and bar3 and bar 4, but I need a little space between bar 2 and bar 3. x. I. ggplot2 (referred to as ggplot) is a powerful graphics package that can be used to make very impressive data visualizations (see contributions to #TidyTueday on Twitter, for example). The points and CI should follow a user-defined color palette, but in addition to that, the filling of the points should change following a logical condition. To reverse dodged element positions in position_jitterdodge(), it is necessary to use a negative value to dodge. Dodging preserves the vertical position of an geom while adjusting the horizontal position. 6 7 19. Defaults to 40% of the resolution of the data. When I add the calls for. 2 for react=x≥09 in red; Risk==0. If the start point of the current interval is greater than “last”, add the end point of the current interval to the output and update “last” to be the end point of the current interval. We have 5 intervals (I added one to the original, to cover the holes case). family: The font family used to draw the dots. 09, 0. Not sure (if you plan to use. 10 Report the odds of success for each predictor variable. If you haven’t already done it, you’ll need to install the ggplot2 library and all its dependencies before running the next command. There are unexpected plot results when specifying the fill aesthetic in geom_bar when the x aesthetic is a Date or POSIXct value. position = "dodge" doesn't work perfectly if the data hasn't been aggregated before plotting. int. ggcoef_table (): a variation of ggcoef_model () adding a table with estimates, confidence intervals and p-values. Length )) + geom_boxplot(aes( colour = Sepal. table (start = value, end = value) setkey (valueDT, start, end. Non-overlapping Intervals 非重叠区间 - Grandyang - 博客园. position_dodge2 is a special case of position_dodge for arranging box plots, which can have variable widths. I am using the ggplot2 package to graph the data and using stat_summary() to obtain a point estimate (mean) and 90% CI within the plot of the data. I am using weight for this. The latter restriction is problematic as it means. "jitter" to use position_jitter), or the result of a call to a position adjustment function. 4) Find the index of maximum element in count array. While the bootstrap actually loses power relative to a perfectly specified model, it is much more robust to changes in the assumptions of that model, and so it retains more power when assumptions are violated. I would like to dodge the position of my bars, but it simply does not do it and I honestly have no clue why. I don't know how to separate the bars. table's and set keys for them. I would transform y_factor to numeric and use continuous y-axis. g. g. I would like to group the intervals (separately for each seqname) using two length cutoffs: one that defines the maximum group length (i. km per bin. Example 1: Input: intervals = [[1,3],[2,6],[8,10],[15,18]] Output: [[1,6],[8,10],[15,18]] Explanation: Since intervals [1,3] and [2,6] overlap, merge them into. My challenge is that within each fill colour, I want to be able to position_dodge () again by the shape so the errorbars and points are not on exactly the same place in the x-axis. dodge. 4000000. geom_text () adds only text to the plot. First, it is necessary to summarize the data. Defaults to 40% of the resolution of the data. width: the amount to dodge in the x direction. 1, 0. A simple approach is to start from the first interval and compare it with all other intervals for overlapping, if it overlaps with any other interval, then remove the other interval from the list and merge the other into the first interval. ~ head(. it might be position = position_dodge (c (-0. position_dodge requires non-overlapping x intervals. Algorithm : Initialize the variable 'answer' with -1. position_dodge requires non-overlapping the changes x intervals Why this happens The reason this happens is because some Nofile hosted of the boxplot /. ply) : position_dodge requires non-overlapping x intervals. # > Warning: position_stack requires non-overlapping x intervals. Of course the points won't match up. 75, the default position_dodge() width. It can bee seen that if you score more than 1. The parameter to be annotated in the plot. 75, the default position_dodge() width. I don't think changing the interval is the solution, as your x-axis is numeric. We can easily achieve this by sorting the intervals by their ending position and then greedily incrementing the counter according to the number of overlaps. . 32, 0. Reload to refresh your session. geom_label () draws a rectangle behind the text, making it easier to read. But converting to a Date class creates an issue with a bar showing erroneous data, layered beside the other bars, and spreading outside of the date range. The graphs in the previous section knit just fine, even though they use almost identical code, including geom_col and position_dodge in the geom_text section. )) call. Other position adjustments: position_dodge(), position_identity(), position_jitterdodge(), position_jitter(),. – rici. It works by plotting the outer perimeter of the polygon. 私のコードはプロットを生成しますが、グラフィックはボックスを描画せず（線のみ表示）、警告メッセージ、 "position_dodge requires non-overlapping x intervals. 12, 0. My identifier is the id column. 我们可以查看函数的帮助文档来获. (Incidentally, you may want to consider switching from geom_bar to geom_col, as the latter uses stat = "identity" by default. R. If you have a query related to it or one of the replies, start a new topic and refer back with a link. 25 (aprroximatley, 1. 9) But none of them worked (actually adding a numeric value granted me with another warning message): Warning message: position_dodge requires non-overlapping x intervals. If you just want to change colors. ggplot(df, aes(x, fill = fill)) + geom_bar(width = 0. " が表示されます。 geom_boxplot(width=5) しかし、これは問題を解決しないようです。どなたか、こ. outlier. If you just want to change colors. This will change the stacking order, and the order of keys in the legend. x, 10)). When I use geom_plot() with position_dodge() for the position argument, I get a warning position_dodge requires non-overlapping x intervals if I use a negative value for width in position_dodge(). Explanation: [1,3] can be removed and the rest of intervals are non-overlapping. stat: The statistical transformation to use on the data for this layer, as a string. Therefore, I think that the behaviour you describe is entirely correct!A function can be created from a formula (e. g. Menggunakan Pie Chart(Koordinat Polar) # Pada dataset ini,saya telah menambahkan kolom,jenis kelamin,umur,dan jumlah # untuk mendapatkan aggregatenya,tetapi tidak merubah keseluruhan kolom. dodge_width : float Amount to dodge in horizontal direction. Is there a way to offset them by line whilst they stay up in the top right corner? – The plot code below makes the segment line congverge at the center of the descrete x variable for all colours. 3900000 PW B Activity 0. It finds overlaps between two sets of intervals. Thanks for contributing an answer to Stack Overflow! Please be sure to answer the question. 04, 1. bulk function. When I use geom_plot () with position_dodge () for the position argument, I get a warning position_dodge requires non-overlapping x intervals if I use a negative. If TRUE, plots the Rate of Germination curves (RoG) instead of the Four-Parameter Hill Function fitted cumulative germination curves (FPHF). I chose values of 3. so far my workaround is to flip coordinates, use geom_errorbar() with position='dodge' and then coord_flip()I get: "Warning message:position_dodge requires non-overlapping x intervals" I typed this message into Google and stackflow seems to advise putting the categorical variable in the x axes (yes I'm still very confused with my x's and y's. 3,4. This geom treats each axis differently and, thus, can thus have two orientations. geom_histogram might do the trick. Image by author. frame(x=abs(rnorm(10)), y = rep(letters[1:5], each=2), z = rep(LETTERS[1:2], 5)) > d x y z 1 1. I've tried changing ggplot's aes width, I tried setting position="dodge", and a bunch of other things. annotate. 2. Stacked bar chart with varying widths in ggplot. See the reference below for details of the models. 0). 75. Then, we might use the following R code: ggplot ( data, aes ( x)) + # Draw ggplot plot with manual xlim geom_histogram () + xlim (- 2. Find centralized, trusted content and collaborate around the technologies you use most. g. This default ensures that bar colours align with the default. Consider increasing max. position: Position adjustment, either as a string, or the result of a call to a position adjustment function. 7)) pos <-position_dodge(width = 0. However, this requires duplicating geom_col and explicitly mapping it on the fill aes. So for example if I had: (1,4) (2,3) (5,8) (6,9) (7,10) I would return (2,3) and (7,8) since these two intervals cover every interval in the set. 9 since my x-axis is date) and adding these arguments to the geom_line, geom_point, and geom_errorbar lines but none have worked so far. jitterdodge. Doing so we could draw separate legends for Urban/Rural and for Male/Female for which the spacing could be set via. A justification-preserving variant of ggplot2::position_dodge() which preserves the vertical position of a geom while adjusting the horizontal position (or vice versa when in a horizontal orientation). The cumulative density curve should include the weight = tonne. Use the latter if you need to change the settings of the adjustment. seed. I shamelessly adapted ideas from both threads below, to which this question is a near-duplicate. A Small Paragraph. Sorted by: 2. 1. It might make sense to at least have the fill color by replicate and then the x-axis showing also the scientist. This can be done by calculating the difference between previous points. Obviously I have to figure out the sizing, but that is just aesthetics and I can figure that out later. Jan 27, 2023A function can be created from a formula (e. 95, which corresponds to a 95 percent confidence interval. I want a column plot in which x defines the x-axis position of the columns, y defines the length of the columns, and the column colors (. html. This is my code: y = c(10. I also obtain the following warning: ymax not defined: adjusting position using y instead Warning message: position_dodge requires non-overlapping x intervals {"payload":{"allShortcutsEnabled":false,"fileTree":{"R":{"items":[{"name":"geom-beeswarm. position = position_dodge(width = -0. shape: shape of outlying points. You don't have to specify the position if you want position_stack(), as it's the default position argument in geom_bar / geom_col. 0. {"payload":{"allShortcutsEnabled":false,"fileTree":{"R":{"items":[{"name":"abstract_geom. 28959034 a B 3 0. systemfit: A. 75; there is no 'reverse' argument. Default is FALSE. height = 0, dodge. . removed = False def maximize_nonoverlapping_count(intervals): intervals = [Interval(start, end) for start,. Non-overlapping Intervals - DEV Community. But it seems your answer implies we can only make it reverse. Warning: position_stack requires non-overlapping x intervals. table) # Using OPs data setDT (intervals_id) setkey (intervals_id, Lower, Upper) # Create dummy intervals (same coordinate) and set key valueDT <- data. jitter. 75`` random_state : int or ~numpy. The docs for geom_col are more specific than what I put in my comment above. If TRUE, plots the Rate of Germination curves (RoG) instead of the Four-Parameter Hill Function fitted cumulative germination curves (FPHF). It works. max given interval x. Here's a quicksect-based O(n**2) implementation of the above algorithm:. I have used position="dodge" but it seems to be not working. By setting position = position_dodge(width = 0) the plot seems to be created as expected without changing the placement of boxes along the x-axis. I want these bars to sum op so the first bars for example need to be equal to 152 on the y-axis. g. Dodge overlapping objects side-to-side, preserving justification Description. The graphs in the previous section knit just fine, even though they use almost identical code, including geom_col and position_dodge in the geom_text section. You signed out in another tab or window. nudge. I would appreciate knowing if this is a feature or a bug in stat_bin (which geom_bar is using) or if I am simply abusing geom_bar. ggcoef_multinom (): a. Dodging preserves the vertical position of an geom while adjusting the horizontal position. – Vasily A. e. Homepage: Asks: position_fill requires non-overlapping x intervals in ggplot I am using ggplot to produce a bar chart stacked by a factor. Instead of using stack you can use pivot_longer for the data preparation. shape: shape of outlying points. absoluteGrob: Absolute grob add_theme: Modify properties of an element in a theme object aes: Construct aesthetic mappings aes_: Define aesthetic mappings programmatically aes_all: Given a character vector, create a set of identity mappings aes_auto: Automatic aesthetic mapping aes_colour_fill_alpha: Colour related aesthetics:. , position_dodge requires non-overlapping x intervals). ## Warning: position_stack requires non-overlapping x intervals ## Warning: Removed 2 rows containing missing values (geom_bar). But you lose control on relevant parts of the aestethics. position. Dodging preserves the vertical position of an geom while adjusting the horizontal position. That's the basis for the plot. x, 10)). The groups are simply placed equidistant from one another. I'm relatively new to R, and I am having issues with avoiding overlapping line ranges using geom_linerange and position_dodge with ggplot. By default, the neighboring violins will touch each other at the widest point if the widest point occurs at the same height. How can I separate the errorbars for different indices? I have used position="dodge" but it seems to be not working. {"payload":{"allShortcutsEnabled":false,"fileTree":{"R":{"items":[{"name":"geom-beeswarm. text and add labels to the legends where you set your desired colors using some HTML and CSS. For color-coding the legend text based on the bars, you can utilize the ggtext package. interaction_plot does the plotting when a trace factor is present. 3 3 19. One option to achieve your desired result would be to use. and the plot will show data in this category spread out along the x axis. This is the first time that I have used ggplot2 outside of a classroom environment, so constructive criticism is highly encouraged. ggplot(test, aes(x=var1, y=value, group=var2, fill=var2)) + geom_boxplot() Warning message: position_dodge requires non-overlapping x intervals I can use facetting; I'm mostly asking the. The errorbars overlap with each other which look really messy. Consider increasing max. equalTo( x intervals; position_dodge2 requires non-overlapping make. stat. Approach: The idea is to compare each intervals as a pair with the help of the Nested loops and then for each interval check that they overlap. Leetcode 435. Alternative 1: overlapping bars with geom_histogram () Dodging preserves the vertical position of an geom while adjusting the horizontal position. 2 将小提琴图水平展示 0. 3. In the box plot we can see the relation between the scored goals of the home team and the result of the match. Dots-specific (aka Slab-specific) aesthetics. Saved searches Use saved searches to filter your results more quickly Don't adjust position current/position_identity. In the original data, I have overlapping time periods, and I want to split them. I keep on getting the error: "Warning message: position_stack requires non-overlapping x intervals". If I render out just Cohort two I also get these weirdly misaligned bars: And Cohort 3 Var 3 to compare. Dodging preserves the vertical position of an geom while adjusting the horizontal position. Repeat the same steps for the remaining intervals after the first. In our analysis, we employed the Mice_Weights dataset available within the dslab package. This means you have to use a point marker style that has a filled interior (see ?pch and scroll down for the available point styles). The x axis is ordered by construction year and bldg name, y axis is energy metric, and I'm trying to make the width of each column proportional to the square footage. To this end we first have to convert the sex column which is mapped on x to a numeric. As you are working with dates, the x axis is on the scale of days. If you haven’t already done it, you’ll need to install the ggplot2 library and all its dependencies before running the next command. position would be on "top" after the coordflip. We need to sort two lists of size N here and run 2 binary searches over them N times. Then we loop over it checking if the next start time is lower then the previous end time. Warning message: position_fill requires non-overlapping x intervals. 3) For each interval [x, y], run a loop for i = x to y and do following in loop. x, 10)). In this case simply insert new interval at the end of the set. )) but with geom_boxplot instead of geom_bar, and it worked. My code produces a plot, but the graphic does not depict the boxes (only shows lines) and I get a warning message, "position_dodge requires non-overlapping x intervals. We find s4, 8 < 10 = true, go to left. Session information1: Removed 2 rows containing missing values (geom_bar). position_fill requires non-overlapping x _have intervals; position_dodge requires non-overlapping .