; file: trapezint.pro ; init: Jan 17 2012 ; last: Oct 1 2013 Rob Rutten ; note from ~/rr/idl/otherlibs/carlsson/util/trapez.pro function trapezint,x0,y0 ;+ ; int=trapezint(x,y) ; performs trapezoidal integration ; from Mats Carlsson ;- ; answer no-parameter query if(n_params(0) lt 2) then begin print,'int=trapezint(x,y)' return,0 endif nx=n_elements(x0) ny=n_elements(y0) if(nx ne ny) then begin print,'trapezint: different number of elements in x and y array' return,-1 endif x=reform(x0) y=reform(y0) integrand=(y(0:ny-2)+y(1:ny-1))*(x(1:nx-1)-x(0:nx-2))*0.5 return,total(integrand) end