added class for storing frequency response objects

1 files changed, 72 insertions, 1 deletions

diff --git a/R/idframe.R b/R/idframe.R
index f8eeef4..18b5e2c 100644
--- a/R/idframe.R
+++ b/R/idframe.R
@@ -160,4 +160,75 @@ print.summary.idframe <- function(object,...){
   
   cat("Inputs \n")
   print(object$inputs)
-}
\ No newline at end of file
+}
+
+#' S3 class for storing frequency response data
+#'
+#' @export
+idfrd <- function(response,freq,Ts){
+  out <- list(response=response,freq=freq,Ts=Ts)
+  class(out) <- "idfrd"
+  return(out)
+}
+
+#' @export
+plot.idfrd <- function(object){
+  require(ggplot2);require(reshape2)
+  
+  mag <- 20*log10(Mod(object$resp)); phase <- Arg(object$resp)
+  sys_df <- data.frame(Frequency = object$freq,Gain = mag,Phase = phase)
+  melted_sys_df <- melt(sys_df, id.var = c("Frequency"))
+  
+  bode <-  ggplot(sys_df, aes(x = Frequency)) + 
+    geom_line() + scale_x_log10()
+  bode_gain <- bode + aes(y = Gain)
+  bode_phase <- bode + aes(y = Phase)
+  
+  multiplot(bode_gain,bode_phase)
+}
+
+# Multiple plot function
+#
+# ggplot objects can be passed in ..., or to plotlist (as a list of ggplot objects)
+# - cols:   Number of columns in layout
+# - layout: A matrix specifying the layout. If present, 'cols' is ignored.
+#
+# If the layout is something like matrix(c(1,2,3,3), nrow=2, byrow=TRUE),
+# then plot 1 will go in the upper left, 2 will go in the upper right, and
+# 3 will go all the way across the bottom.
+#
+multiplot <- function(..., plotlist=NULL, file, cols=1, layout=NULL) {
+  library(grid)
+  
+  # Make a list from the ... arguments and plotlist
+  plots <- c(list(...), plotlist)
+  
+  numPlots = length(plots)
+  
+  # If layout is NULL, then use 'cols' to determine layout
+  if (is.null(layout)) {
+    # Make the panel
+    # ncol: Number of columns of plots
+    # nrow: Number of rows needed, calculated from # of cols
+    layout <- matrix(seq(1, cols * ceiling(numPlots/cols)),
+                     ncol = cols, nrow = ceiling(numPlots/cols))
+  }
+  
+  if (numPlots==1) {
+    print(plots[[1]])
+    
+  } else {
+    # Set up the page
+    grid.newpage()
+    pushViewport(viewport(layout = grid.layout(nrow(layout), ncol(layout))))
+    
+    # Make each plot, in the correct location
+    for (i in 1:numPlots) {
+      # Get the i,j matrix positions of the regions that contain this subplot
+      matchidx <- as.data.frame(which(layout == i, arr.ind = TRUE))
+      
+      print(plots[[i]], vp = viewport(layout.pos.row = matchidx$row,
+                                      layout.pos.col = matchidx$col))
+    }
+  }
+}