2016 Update

2016-12-05 22:15:40 +01:00 · 2016-12-05 22:15:40 +01:00 · dcf5d15da3
commit dcf5d15da3
parent 948b86eafa
7965 changed files with 139854 additions and 31002 deletions
--- a/Task/Extreme-floating-point-values/Fortran/extreme-floating-point-values-1.f
+++ b/Task/Extreme-floating-point-values/Fortran/extreme-floating-point-values-1.f
@ -0,0 +1,8 @@
+       REAL*8		BAD,NaN			!Sometimes a number is not what is appropriate.
+       PARAMETER (NaN = Z'FFFFFFFFFFFFFFFF')	!This value is recognised in floating-point arithmetic.
+       PARAMETER (BAD = Z'FFFFFFFFFFFFFFFF')	!I pay special attention to BAD values.
+       CHARACTER*3	BADASTEXT		!Speakable form.
+       DATA		BADASTEXT/" ? "/	!Room for "NaN", short for "Not a Number", if desired.
+       REAL*8		PINF,NINF		!Special values. No sign of an "overflow" state, damnit.
+       PARAMETER (PINF = Z'7FF0000000000000')	!May well cause confusion
+       PARAMETER (NINF = Z'FFF0000000000000')	!On a cpu not using this scheme.
--- a/Task/Extreme-floating-point-values/Fortran/extreme-floating-point-values-2.f
+++ b/Task/Extreme-floating-point-values/Fortran/extreme-floating-point-values-2.f
@ -0,0 +1,78 @@
+Cause various arithmetic errors to see what sort of hissy fit is thrown.
+      REAL X2,X3,X4,Y4,XX,ZERO
+      INTEGER IX4,IY4
+      EQUIVALENCE (X4,IX4),(Y4,IY4)	!To view bits without provoking special fp handling.
+      REAL*4 NaN4
+      PARAMETER (NaN4 = Z'FFC00000')	!FFFFFFFF
+c      PARAMETER (NaN4 = Z'FFFFFFFF')	!FFFFFFFF
+      REAL*8 NaN8,X8(5),Y8,INF8
+      PARAMETER (NaN8 = Z'FFF8000000000000')	!FFFFFFFF
+c      PARAMETER (NaN8 = Z'FFFFFFFFFFFFFFFF')
+      LOGICAL LX(5)
+      INTEGER I
+      X4 = NaN4
+      WRITE (6,1) X4,IX4
+    1 FORMAT ("X4 =",F12.4,' Hex ',Z8)
+      WRITE (6,*) "Test X4 .EQ. Bad?  ",X4.EQ.NaN4
+      WRITE (6,*) "Test X4 .NE. Bad?  ",X4.NE.NaN4
+      WRITE (6,*) "Test IsNaN(X4)  ",ISNAN(X4)
+      WRITE (6,*) "Test Abs(bad)   ",ABS(X4)
+c      WRITE (6,*) "Test Exp(bad)",EXP(X4)
+      Y8 = HUGE(Y8)
+      WRITE(6,*) "Huge",Y8,LOG(Y8)
+      Y8 = LOG(Y8)
+      WRITE (6,*) "Hic",EXP(Y8)
+
+      X2 = 0
+      X3 = 0
+      ZERO = 0
+      XX = 666.66
+      X2 = XX + X4
+      WRITE (6,*) "Test x + BAD    ",X2
+      WRITE (6,*) "Test 0/0        ",X3/ZERO
+      WRITE (6,*) "Test 1/0        ",1/ZERO
+      WRITE (6,*) "Test-1/0        ",-1/ZERO
+      X2 = MIN(XX,X4)
+      WRITE (6,*) "Test min(x,Bad) ",X2
+      WRITE (6,*) "Test min(x,NaN4)",MIN(XX,NaN4)
+c      WRITE (6,*) "Test mod(x,Bad) ",MOD(XX,X4)
+c      WRITE (6,*) "Test mod(Bad,x) ",MOD(X4,XX)
+c      WRITE (6,*) "Test mod(x,0)   ",MOD(XX,Z)
+c      WRITE (6,*) "Sqrt(Bad)",SQRT(X4)
+
+      DO I = 1,0,-1	!for sqrt(-1), a snarl.
+        X4 = I
+        X4 = X4/FLOAT(I)
+        Y4 = SQRT(FLOAT(I))
+        WRITE (6,10) I,I,X4,IX4,I,Y4,IY4
+   10   FORMAT (I3,"/",I3," gives",F9.5," Hex ",Z8,
+     1   ", Sqrt(",I3,") gives",F9.5," Hex ",Z8)
+      END DO
+
+Contemplate double precision.
+      WRITE (6,*)
+      WRITE (6,*) "Problems with IsNaN and arrays..."
+      DO I = 1,5
+        X8(I) = I
+      END DO
+      X8(3:4) = NaN8
+      WRITE (6,*) "X=",X8
+      WRITE (6,*) "X(2:4)=",X8(2:4)
+      WRITE (6,*) "isnan(x(2:4))",ISNAN(X8(2:4))
+      WRITE (6,*) "isnan(x(2))..(4))",ISNAN(X8(2)),ISNAN(X8(3)),
+     1 ISNAN(X8(4))
+      WRITE (6,*) "abs(x(2:4))",ABS(X8(2:4))
+      WRITE (6,*) "isnan(abs(x(2:4)))",ISNAN(ABS(X8(2:4)))
+      LX = ISNAN(X8)
+      WRITE (6,*) "LX = isnan(X)",LX
+
+      XX = HUGE(XX)
+      WRITE(6,*) "Huge(x)=",XX,-XX
+      XX = 1/ZERO
+      WRITE(6,11) XX,-XX
+   11 FORMAT("1/Zero=",Z8,", neg ",Z8)
+      INF8 = XX
+      WRITE (6,12) INF8,-INF8
+   12 FORMAT("1/Zero=",Z16,", neg ",Z16)
+      WRITE (6,*) "Burp!"
+      END