add a function to compute log(n) for integer n

This commit adds the function ln() to compute log(n) for integer n. It uses a
lookup table for n < 100 to speed things up.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/misc.h b/src/misc.h
index eb62e46..6e9095a 100644
--- a/src/misc.h
+++ b/src/misc.h
@@ -3,8 +3,10 @@
 
 #include <stdlib.h> /* for size_t */
 
+#define LN_MAX 100
 #define LNFACT_MAX 100
 
+double ln(unsigned int n);
 double lnfact(unsigned int n);
 double kahan_sum(double *x, size_t n);
 double interp1d(double x, double *xp, double *yp, size_t n);