--- title: "Plotting Composite Material Data" author: "Ally Fraser" date: "2-May-2020" output: rmarkdown::html_vignette vignette: > %\VignetteIndexEntry{Plotting Composite Material Data} %\VignetteEngine{knitr::rmarkdown} %\VignetteEncoding{UTF-8} --- ```{r setup, include = FALSE} knitr::opts_chunk$set( collapse = TRUE, comment = "#>", fig.width = 6 ) # If any of the required packages are unavailable, # don't re-run the code # nolint start required <- c("dplyr", "ggplot2", "tidyr", "cmstatr") if (!all(unlist(lapply(required, function(pkg) { requireNamespace(pkg, quietly = TRUE)} )))) { knitr::opts_chunk$set(eval = FALSE) } # nolint end ``` This vignette demonstrates how to create some of the graphs commonly used when analyzing composite material data. Here, we rely on the [`ggplot2`](https://ggplot2.tidyverse.org/) package for graphing. This package can be loaded either on its own, or through the `tidyverse` meta-package, which also includes packages such as `dplyr` that we will also use. We'll need to load a few packages in order to proceed. ```{r message=FALSE} library(dplyr) library(ggplot2) library(tidyr) library(cmstatr) ``` Throughout this vignette, we'll use one of the example data sets that comes with `cmstatr` and we'll focus on the warp-tension data as an example. We'll load the example data in a variable as follows. By default the condition will be in an arbitrary order, but throughout the visualization, we'll want the conditions shown in a particular order (from coldest and driest to hottest and wettest). We can define the order of the conditions using the `ordered` function. For brevity, only the first few rows of the data set are displayed below. ```{r} dat <- carbon.fabric.2 %>% filter(test == "WT") %>% mutate(condition = ordered(condition, c("CTD", "RTD", "ETW", "ETW2"))) dat %>% head(10) ``` We'll then calculate the B-Basis value using the pooling by standard deviation method. This data set happens to fail some of the diagnostic tests, but for the purpose of this example, we'll ignore those failures using the `override` argument. ```{r} b_basis_pooled <- dat %>% basis_pooled_cv(strength, condition, batch, override = c("between_group_variability", "normalized_variance_equal")) b_basis_pooled ``` The object returned from `basis_pooled_cv` contains a number of values. One value is a `data.frame` containing the groups (i.e. conditions) and the corresponding basis values. This looks like the following. We'll use this in the visualizations. ```{r} b_basis_pooled$basis ``` # Batch Plots Batch plots are used to identify differences between batches. Simple batch plots can be created using box plots and adding horizontal lines for the basis values as follows. Note that the heavy line in the box of the box plot is the *median*, not the mean. The two hinges correspond with the first and third quantiles and the whiskers extend to the most extreme data point, or 1.5 times the inner quantile range. In the code below, we use the function `rename` to rename the column `group` to `condition`. The `data.frame` produced by `basis_pooled_cv` uses the columns `value` and `group`, but to match the data, we need the column with the conditions to be named `condition`. ```{r} dat %>% ggplot(aes(x = batch, y = strength)) + geom_boxplot() + geom_jitter(width = 0.25) + geom_hline(aes(yintercept = value), data = b_basis_pooled$basis %>% rename(condition = group), color = "blue") + facet_grid(. ~ condition) + theme_bw() + ggtitle("Batch Plot") ``` It's sometimes useful add failure modes to the plot so that you can easily identify whether failure modes differ between conditions or batches. This can be done with the `geom_jitter_failure_mode()` function. This behaves very similarly to `geom_jitter()`, except that `color` or `shape` must be specified, and if there are multiple failure modes (e.g. "LAB/LAT"), both failure modes are plotted as separate points. ```{r} dat %>% ggplot(aes(x = batch, y = strength)) + geom_boxplot() + geom_jitter_failure_mode(aes(color = failure_mode, shape = failure_mode), width = 0.25) + geom_hline(aes(yintercept = value), data = b_basis_pooled$basis %>% rename(condition = group), color = "blue") + facet_grid(. ~ condition) + theme_bw() + ggtitle("Batch Plot with Failure Modes") ``` # Quantile Plots A quantile plot provides a graphical summary of sample values. This plot displays the sample values and the corresponding quantile. A quantile plot can be used to examine the symmetry and tail sizes of the underlying distribution. Sharp rises may indicate the presence of outliers. ```{r} dat %>% ggplot(aes(x = strength, color = condition)) + stat_ecdf(geom = "point") + coord_flip() + theme_bw() + ggtitle("Quantile Plot") ``` # Normal Survival Function Plots An empirical survival function, and the corresponding normal survival function can be plotted using two `ggplot` "stat" functions provided by `cmstatr`. In the example below, the empirical survival function is plotted for each condition, and the survival function for a normal distribution with the mean and variance from the data is also plotted (the survival function is 1 minus the cumulative distribution function). This type of plot can be used to identify how closely the data follows a normal distribution, and also to compare the distributions of the various conditions. ```{r} dat %>% ggplot(aes(x = strength, color = condition)) + stat_normal_surv_func() + stat_esf() + theme_bw() + ggtitle("Normal Survival Function Plot") ``` # Normal Score Plots The normal scores plot calculates the normal score and plots it against the normal score. Normal plots are useful to investigate distributions of the data. ```{r} dat %>% group_by(condition) %>% mutate(norm.score = scale(strength)) %>% ggplot(aes(x = norm.score, y = strength, colour = condition)) + geom_point() + ggtitle("Normal Scores Plot") + theme_bw() ``` # Q-Q Plots A Q-Q plot compares the data against the theoretical quantiles for a particular distribution. A line is also plotted showing the normal distribution with mean and variance from the data. If the data exactly followed a normal distribution, all points would fall on this line. ```{r} dat %>% ggplot(aes(sample = strength, colour = condition)) + geom_qq() + geom_qq_line() + ggtitle("Q-Q Plot") + theme_bw() ``` # Property Plots Property plots allow for a variety of properties for a group to be compared to other properties within the same group, as well as to other group properties. The properties included in this plot are A-Basis, B-Basis, Pooled A- and B-Basis, Pooled Modified CV (Coefficient of Variation) A- and B-Basis, Mean, and Min for each group. The property plots will take a bit of work to construct. First, the distribution of each group must be determined. Once the distribution has been determined, the proper basis calculation based on that distribution should be filled in below. We also have a column in the tables below for extra arguments to pass to the `basis` function, such as overrides required or the method for the `basis_hk_ext` function to use. ```{r} b_basis_fcn <- tribble( ~condition, ~fcn, ~args, "CTD", "basis_normal", list(override = c("between_batch_variability")), "RTD", "basis_normal", list(override = c("between_batch_variability")), "ETW", "basis_hk_ext", NULL, "ETW2", "basis_normal", list(override = c("between_batch_variability")) ) a_basis_fcn <- tribble( ~condition, ~fcn, ~args, "CTD", "basis_normal", list(override = c("between_batch_variability")), "RTD", "basis_normal", list(override = c("between_batch_variability")), "ETW", "basis_hk_ext", list(method = "woodward-frawley"), "ETW2", "basis_normal", list(override = c("between_batch_variability")) ) ``` We'll write a function that takes the data and information about the distribution and computes the single-point basis value. We'll use this function for both A- and B-Basis, so we'll add a parameter for the probability (0.90 or 0.99). ```{r} single_point_fcn <- function(group_x, group_batch, cond, basis_fcn, p) { fcn <- basis_fcn$fcn[basis_fcn$condition == cond[1]] extra_args <- basis_fcn$args[basis_fcn$condition == cond[1]] args <- c( list(x = group_x, batch = group_batch, p = p), unlist(extra_args)) basis <- do.call(fcn, args) basis$basis } single_point_results <- dat %>% group_by(condition) %>% summarise(single_point_b_basis = single_point_fcn( strength, batch, condition, b_basis_fcn, 0.90), single_point_a_basis = single_point_fcn( strength, batch, condition, a_basis_fcn, 0.99), minimum = min(strength), mean = mean(strength)) %>% mutate(condition = ordered(condition, c("CTD", "RTD", "ETW", "ETW2"))) single_point_results ``` In the above code, we also ensure that the condition column is still in the order we expect. We've already computed the B-Basis of the data using a pooling method. We'll do the same for A-Basis: ```{r} a_basis_pooled <- dat %>% basis_pooled_cv(strength, condition, batch, p = 0.99, override = c("between_group_variability", "normalized_variance_equal")) a_basis_pooled ``` As we saw before, the returned object has a property called `basis`, which is a `data.frame` for the pooling methods. ```{r} a_basis_pooled$basis ``` We can take this `data.frame` and change the column names to suit our needs. ```{r} a_basis_pooled$basis %>% rename(condition = group, b_basis_pooled = value) ``` We can combine all these steps into one statement. We'll also ensure that the conditions are listed in the order we want. ```{r} a_basis_pooled_results <- a_basis_pooled$basis %>% rename(condition = group, a_basis_pooled = value) %>% mutate(condition = ordered(condition, c("CTD", "RTD", "ETW", "ETW2"))) a_basis_pooled_results ``` And the same thing for B-Basis: ```{r} b_basis_pooled_results <- b_basis_pooled$basis %>% rename(condition = group, b_basis_pooled = value) %>% mutate(condition = ordered(condition, c("CTD", "RTD", "ETW", "ETW2"))) b_basis_pooled_results ``` We can use the function `inner_join` from the `dplyr` package to combine the three sets of computational results. Each row for each condition will be concatenated. ```{r} single_point_results %>% inner_join(b_basis_pooled_results, by = "condition") %>% inner_join(a_basis_pooled_results, by = "condition") ``` To use this table in the plot we're trying to construct, we want to "lengthen" the table as follows. ```{r} single_point_results %>% inner_join(b_basis_pooled_results, by = "condition") %>% inner_join(a_basis_pooled_results, by = "condition") %>% pivot_longer(cols = single_point_b_basis:a_basis_pooled) ``` We can now make a plot based on this: ```{r} single_point_results %>% inner_join(b_basis_pooled_results, by = "condition") %>% inner_join(a_basis_pooled_results, by = "condition") %>% pivot_longer(cols = single_point_b_basis:a_basis_pooled) %>% ggplot(aes(x = condition, y = value)) + geom_boxplot(aes(y = strength), data = dat) + geom_point(aes(shape = name, color = name)) + ggtitle("Property Graph") + theme_bw() ``` # Nested Data Plots `cmstatr` contains the function `nested_data_plot`. This function creates a plot showing the sources of variation. In the following example, the data is grouped according to the variables in the `group` argument. The data is first grouped according to `batch`, then according to `panel`. The labels located according to the data points that fall under them. By default, the mean is used, but that `stat` argument can be used to locate the labels according to `median` or some other statistic. ```{r} carbon.fabric.2 %>% mutate(panel = as.character(panel)) %>% filter(test == "WT") %>% nested_data_plot(strength, groups = c(batch, panel)) ``` Optionally, `fill` or `color` can be set as follows: ```{r} carbon.fabric.2 %>% mutate(panel = as.character(panel)) %>% filter(test == "WT" & condition == "RTD") %>% nested_data_plot(strength, groups = c(batch, panel), fill = batch, color = panel) ```