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March 2014 update

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This commit is contained in:
Ingy döt Net 2014-04-02 16:56:35 +00:00
parent 09687c4926
commit a25938f123
1846 changed files with 21876 additions and 5203 deletions
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29
Task/Pascals-triangle-Puzzle/D/pascals-triangle-puzzle.d
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@ -1,12 +1,13 @@
import std.stdio, std.algorithm;
void iterate(bool doPrint=true)(double[] v, double[] diff) {
void iterate(bool doPrint=true)(double[] v, double[] diff)
/*pure nothrow*/ {
static ref T E(T)(T[] x, in size_t row, in size_t col)
pure nothrow {
return x[row * (row + 1) / 2 + col];
}
double sum = 0.0;
double tot = 0.0;
do {
// enforce boundary conditions
E(v, 0, 0) = 151;
@ -15,8 +16,8 @@ void iterate(bool doPrint=true)(double[] v, double[] diff) {
E(v, 4, 3) = 4;
// calculate difference from equilibrium
foreach (i; 1 .. 5) {
foreach (j; 0 .. i + 1) {
foreach (immutable i; 1 .. 5) {
foreach (immutable j; 0 .. i + 1) {
E(diff, i, j) = 0;
if (j < i)
E(diff, i, j) += E(v, i - 1, j) -
@ -29,8 +30,8 @@ void iterate(bool doPrint=true)(double[] v, double[] diff) {
}
}
foreach (i; 1 .. 4)
foreach (j; 0 .. i)
foreach (immutable i; 1 .. 4)
foreach (immutable j; 0 .. i)
E(diff, i, j) += E(v, i + 1, j) +
E(v, i + 1, j + 1) -
E(v, i, j);
@ -40,22 +41,22 @@ void iterate(bool doPrint=true)(double[] v, double[] diff) {
// do feedback, check if we are close enough
// 4: scale down the feedback to avoid oscillations
v[] += diff[] / 4;
sum = reduce!q{a + b ^^ 2}(0.0, diff);
tot = diff.map!q{ a ^^ 2 }.sum;
static if (doPrint)
writeln("dev: ", sum);
writeln("dev: ", tot);
// sum(dx^2) < 0.1 means each cell is no more than 0.5 away
// tot(dx^2) < 0.1 means each cell is no more than 0.5 away
// from equilibrium. It takes about 50 iterations. After
// 700 iterations sum is < 1e-25, but that's overkill.
} while (sum >= 0.1);
// 700 iterations tot is < 1e-25, but that's overkill.
} while (tot >= 0.1);
}
void main() {
static void show(in double[] x) {
static void show(in double[] x) nothrow {
int idx;
foreach (i; 0 .. 5)
foreach (j; 0 .. i+1) {
foreach (immutable i; 0 .. 5)
foreach (immutable j; 0 .. i+1) {
printf("%4d%c", cast(int)(0.5 + x[idx]),
j < i ? ' ' : '\n');
idx++;