add all scripts/tools

1 files changed, 21 insertions, 0 deletions

diff --git a/r/chisq.R b/r/chisq.R
new file mode 100644
index 0000000..41f851f
--- /dev/null
+++ b/r/chisq.R
@@ -0,0 +1,21 @@
+# -*- coding: utf-8 -*-
+#
+# Calculate the chi-squared values between the given data and model values.
+#
+
+calc.chisq <- function(value, error=NULL, model=NULL) {
+    if (is.data.frame(value)) {
+        df <- value
+        value <- df$value
+        error <- df$error
+        model <- df$model
+    }
+    chisq <- (value - model)^2
+    if (! is.null(error)) {
+        weights <- error ^ (-2)
+        chisq <- chisq * weights
+    }
+    return(sum(chisq))
+}
+
+#  vim: set ts=8 sw=4 tw=0 fenc=utf-8 ft=r: #