Added a small performance test of BLAS routines.

tests/small-testcodes/blas_performance.f90

+program test_blas
+  INTEGER,PARAMETER::M=200,N=20000
+
+  COMPLEX :: A(N,M),B(N,M),C(N,N)
+  COMPLEX :: AA(M,M)
+  REAL    :: R(N,M,4)
+  REAL    :: time1,time2
+
+  CALL cpu_time(time1)
+  CALL random_number(r)
+  A=cmplx(R(:,:,1),R(:,:,2))
+  B=cmplx(R(:,:,3),R(:,:,4))
+  C=0.0
+  AA=cmplx(R(:M,:,1),R(:M,:,3))
+  DO i=1,M
+     DO j=1,i
+        AA(i,j)=conjg(AA(j,i))
+     ENDDO
+     AA(i,i)=i*10
+  ENDDO
+
+  CALL cpu_time(time2)
+  print *, "Init:",time2-time1
+
+  CALL cpu_time(time1)
+  CALL zgemm("N","T",N,N,M,cmplx(1.,0),A,N,B,N,cmplx(1.,0),C,N)
+  CALL cpu_time(time2)
+  print *, "zgemm:",time2-time1
+
+  CALL cpu_time(time1)
+  CALL zherk("U","N",N,M,cmplx(1.,0),A,N,cmplx(1.,0),C,N)
+  CALL cpu_time(time2)
+  print *, "zherk:",time2-time1
+
+  CALL cpu_time(time1)
+  CALL zher2k("U","N",N,M,cmplx(1.,0),A,N,B,N,cmplx(1.,0),C,N)
+  CALL cpu_time(time2)
+  print *, "zher2k:",time2-time1
+
+  CALL cpu_time(time1)
+  CALL zpotrf("U",M,AA,M,i)
+  CALL cpu_time(time2)
+  print *, "zpotrf:",time2-time1
+  print *,i
+  
+end
+