# Changes

## TriForce

, 13:17, 8 April 2019
Kernel Optimization Attempts
[[File:Julia.jpg]]
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This problem would be fairly simple to parallelize. In the image created by Julia sets each pixel is independent of the others. This problem involves Complex numbers, but that can be simply represented by using two arrays, or pairs of floats.
==== Assignment 1: Selection for parallelizing ====
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Change : Quickly finds one section that requires a single value in one spot, by checking all sections at once and remembering a single valuesection
Theory : Similar to the previous Kernel, trying to remove the second loop
Result : Surprisingly slow, gains little benefit from the section logic and shared memory, yet is still required to count all values
Result : Not faster, HOWEVER there is a slight error, by setting notSeen = 0, the section counters will rarely reach one
{| class="wikitable mw-collapsible mw-collapsed"
! CountDown - using Int as Boolean Array(EDITED now 4.28 seconds)
|-
|
int notSeen = 0; //Boolean Array as an Integer
if (gridIdx == 0)
changed = true;
rowHas[col][row] = false;
colHas[col][row] = false;
}
// Previous loop has not changed any values
while (changed) {
if (gridIdx == 0) // forget previous change
changed = false;
bool inSection = true;
int b_shuttle = 1;
for (int idx = 0; idx < N; ++idx) {
// Ensures that every square in each section is working on a different number in the section
int num = (idx + offset) % N;
if (b_shuttle & notSeen) {&& if (at != UNASSIGNED || rowHas[row][num] || boxHas[box][num] || colHas[col][num])) { notSeen ^= b_shuttle; --count;
rowCount[row][num]--;
colCount[col][num]--;
boxCount[box][num]--;
} else if (inSection) { guess notSeen ^= numb_shuttle; } --count;
}
if ((b_shuttle & notSeen) && (count == 1 || rowCount[row][num] == 1 || boxCount[box][num] == 1 || colCount[col][num] == 1)){ rowHas[row][num] = true; inSection colHas[col][num] = falsetrue; boxHas[box][num] = true; changed = true; notSeen ^= b_shuttle; at = num + 1; count = 0; }
b_shuttle <<= 1;
}
if (count == 1 || !inSection) {
at = guess + 1;
notSeen = count = 0;
rowHas[row][guess] = true;
colHas[col][guess] = true;
boxHas[box][guess] = true;
changed = true;
}
if (changed && gridIdx == 0)
at = 0;
d_a[gridIdx] = at;
}
{| class="wikitable mw-collapsible mw-collapsed"
! Countdown Boolean Array(EDITED - now 4.37ms)
|-
|
int count = 0; //Number of values which can fit in this square
bool notSeen[N]; //Boolean Array as an Integer
for (int i idx = 0; i idx < N; ++iidx) notSeen[iidx] = false; if (gridIdx == 0) changed = true;
if (gridIdx == 0)
changed = true;

rowHas[col][row] = false;
colHas[col][row] = false;
if (at == UNASSIGNED && !(rowHas[row][num] || boxHas[box][num] || colHas[col][num])) {
notSeen[num] = true; //this value can go here
++count; //how many values this square can have
guess = num;
//how many values this section can have
at = guess + 1;
count = 0;
notSeen[guess] = false;
rowHas[row][guess] = true;
colHas[col][guess] = true;
}
// Previous loop has not changed any values
while (changed) {
if (gridIdx == 0) // forget previous change
changed = false;
bool inSection = true; for (int idx = 0; idx < N; ++idx) {
// Ensures that every square in each section is working on a different number in the section
int num = (idx + offset) % N;
if (at == UNASSIGNED && notSeen[num]) {&& if (at != UNASSIGNED || rowHas[row][num] || boxHas[box][num] || colHas[col][num])) { notSeen[num] = false; --count;
rowCount[row][num]--;
colCount[col][num]--;
boxCount[box][num]--;
} else if (inSection) { guess notSeen[num] = numfalse; } --count;
}