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+# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+
+# ALOG -- Compute the logarithm to the base 10 of a vector (generic). If the
+# logarithm is undefined (x <= 0) a user supplied function is called to get
+# the function value.
+
+procedure alogr (a, b, npix, errfcn)
+
+real a[ARB], b[ARB]
+int npix, i
+extern errfcn()
+real errfcn()
+errchk errfcn
+
+begin
+ do i = 1, npix {
+ if (a[i] <= 0.0)
+ b[i] = errfcn (a[i])
+ else {
+ # Note Fortran standard forbids log10(cplx).
+ b[i] = log10 (a[i])
+ }
+ }
+end