1 2 #include <../src/sys/classes/draw/utils/axisimpl.h> /*I "petscdraw.h" I*/ 3 4 #undef __FUNCT__ 5 #define __FUNCT__ "PetscADefLabel" 6 /* 7 val is the label value. sep is the separation to the next (or previous) 8 label; this is useful in determining how many significant figures to 9 keep. 10 */ 11 PetscErrorCode PetscADefLabel(PetscReal val,PetscReal sep,char **p) 12 { 13 static char buf[40]; 14 PetscErrorCode ierr; 15 16 PetscFunctionBegin; 17 /* Find the string */ 18 if (PetscAbsReal(val)/sep < 1.e-4) { 19 buf[0] = '0'; buf[1] = 0; 20 } else { 21 sprintf(buf,"%0.1e",(double)val); 22 ierr = PetscStripZerosPlus(buf);CHKERRQ(ierr); 23 ierr = PetscStripe0(buf);CHKERRQ(ierr); 24 ierr = PetscStripInitialZero(buf);CHKERRQ(ierr); 25 ierr = PetscStripAllZeros(buf);CHKERRQ(ierr); 26 ierr = PetscStripTrailingZeros(buf);CHKERRQ(ierr); 27 } 28 *p = buf; 29 PetscFunctionReturn(0); 30 } 31 32 #undef __FUNCT__ 33 #define __FUNCT__ "PetscADefTicks" 34 /* Finds "nice" locations for the ticks */ 35 PetscErrorCode PetscADefTicks(PetscReal low,PetscReal high,int num,int *ntick,PetscReal *tickloc,int maxtick) 36 { 37 PetscErrorCode ierr; 38 int i,power; 39 PetscReal x = 0.0,base=0.0,eps; 40 41 PetscFunctionBegin; 42 ierr = PetscAGetBase(low,high,num,&base,&power);CHKERRQ(ierr); 43 ierr = PetscAGetNice(low,base,-1,&x);CHKERRQ(ierr); 44 45 /* Values are of the form j * base */ 46 /* Find the starting value */ 47 if (x < low) x += base; 48 49 i = 0; eps = base/10; 50 while (i < maxtick && x <= high+eps) { 51 tickloc[i++] = x; x += base; 52 } 53 *ntick = i; 54 tickloc[i-1] = PetscMin(tickloc[i-1],high); 55 56 if (i < 2 && num < 10) { 57 ierr = PetscADefTicks(low,high,num+1,ntick,tickloc,maxtick);CHKERRQ(ierr); 58 } 59 PetscFunctionReturn(0); 60 } 61 62 #define EPS 1.e-6 63 64 #undef __FUNCT__ 65 #define __FUNCT__ "PetscExp10" 66 PetscErrorCode PetscExp10(PetscReal d,PetscReal *result) 67 { 68 PetscFunctionBegin; 69 *result = PetscPowReal((PetscReal)10.0,d); 70 PetscFunctionReturn(0); 71 } 72 73 #undef __FUNCT__ 74 #define __FUNCT__ "PetscMod" 75 PetscErrorCode PetscMod(PetscReal x,PetscReal y,PetscReal *result) 76 { 77 int i; 78 79 PetscFunctionBegin; 80 if (y == 1) { 81 *result = 0.0; 82 PetscFunctionReturn(0); 83 } 84 i = ((int)x) / ((int)y); 85 x = x - i * y; 86 while (x > y) x -= y; 87 *result = x; 88 PetscFunctionReturn(0); 89 } 90 91 #undef __FUNCT__ 92 #define __FUNCT__ "PetscCopysign" 93 PetscErrorCode PetscCopysign(PetscReal a,PetscReal b,PetscReal *result) 94 { 95 PetscFunctionBegin; 96 if (b >= 0) *result = a; 97 else *result = -a; 98 PetscFunctionReturn(0); 99 } 100 101 #undef __FUNCT__ 102 #define __FUNCT__ "PetscAGetNice" 103 /* 104 Given a value "in" and a "base", return a nice value. 105 based on "sign", extend up (+1) or down (-1) 106 */ 107 PetscErrorCode PetscAGetNice(PetscReal in,PetscReal base,int sign,PetscReal *result) 108 { 109 PetscReal etmp,s,s2,m; 110 PetscErrorCode ierr; 111 112 PetscFunctionBegin; 113 ierr = PetscCopysign (0.5,(double)sign,&s);CHKERRQ(ierr); 114 etmp = in / base + 0.5 + s; 115 ierr = PetscCopysign (0.5,etmp,&s);CHKERRQ(ierr); 116 ierr = PetscCopysign (EPS * etmp,(double)sign,&s2);CHKERRQ(ierr); 117 etmp = etmp - 0.5 + s - s2; 118 ierr = PetscMod(etmp,1.0,&m);CHKERRQ(ierr); 119 etmp = base * (etmp - m); 120 *result = etmp; 121 PetscFunctionReturn(0); 122 } 123 124 #undef __FUNCT__ 125 #define __FUNCT__ "PetscAGetBase" 126 PetscErrorCode PetscAGetBase(PetscReal vmin,PetscReal vmax,int num,PetscReal *Base,int *power) 127 { 128 PetscReal base,ftemp,e10; 129 static PetscReal base_try[5] = {10.0,5.0,2.0,1.0,0.5}; 130 PetscErrorCode ierr; 131 int i; 132 133 PetscFunctionBegin; 134 /* labels of the form n * BASE */ 135 /* get an approximate value for BASE */ 136 base = (vmax - vmin) / (double)(num + 1); 137 138 /* make it of form m x 10^power, m in [1.0, 10) */ 139 if (base <= 0.0) { 140 base = PetscAbsReal(vmin); 141 if (base < 1.0) base = 1.0; 142 } 143 ftemp = PetscLog10Real((1.0 + EPS) * base); 144 if (ftemp < 0.0) ftemp -= 1.0; 145 *power = (int)ftemp; 146 ierr = PetscExp10((double)-*power,&e10);CHKERRQ(ierr); 147 base = base * e10; 148 if (base < 1.0) base = 1.0; 149 /* now reduce it to one of 1, 2, or 5 */ 150 for (i=1; i<5; i++) { 151 if (base >= base_try[i]) { 152 ierr = PetscExp10((double)*power,&e10);CHKERRQ(ierr); 153 base = base_try[i-1] * e10; 154 if (i == 1) *power = *power + 1; 155 break; 156 } 157 } 158 *Base = base; 159 PetscFunctionReturn(0); 160 } 161