Introduction - If you have any usage issues, please Google them yourself
Correlation coefficient r between two series
c x(i) and y(i) with missing data, where i=1,...,n.
c input: x(n),y(n),undef
c undef is missing data however, if ax or sx is still undefined,
c it will be-9.99e33 whatever the input undef is.
c output: r and nr
c nr is the effective number of independent and defined values
c simultianeuosly in two series.
c By Dr. LI Jianping, Decmber 5, 2001.