56 lines
1.7 KiB
Go
56 lines
1.7 KiB
Go
package spec_iterator
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func ParallelizedIndexRange(length int, parallelTotal int, parallelNode int) (startIndex int, count int) {
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if length == 0 {
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return 0, 0
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}
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// We have more nodes than tests. Trivial case.
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if parallelTotal >= length {
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if parallelNode > length {
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return 0, 0
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} else {
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return parallelNode - 1, 1
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}
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}
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// This is the minimum amount of tests that a node will be required to run
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minTestsPerNode := length / parallelTotal
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// This is the maximum amount of tests that a node will be required to run
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// The algorithm guarantees that this would be equal to at least the minimum amount
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// and at most one more
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maxTestsPerNode := minTestsPerNode
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if length%parallelTotal != 0 {
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maxTestsPerNode++
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}
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// Number of nodes that will have to run the maximum amount of tests per node
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numMaxLoadNodes := length % parallelTotal
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// Number of nodes that precede the current node and will have to run the maximum amount of tests per node
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var numPrecedingMaxLoadNodes int
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if parallelNode > numMaxLoadNodes {
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numPrecedingMaxLoadNodes = numMaxLoadNodes
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} else {
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numPrecedingMaxLoadNodes = parallelNode - 1
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}
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// Number of nodes that precede the current node and will have to run the minimum amount of tests per node
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var numPrecedingMinLoadNodes int
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if parallelNode <= numMaxLoadNodes {
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numPrecedingMinLoadNodes = 0
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} else {
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numPrecedingMinLoadNodes = parallelNode - numMaxLoadNodes - 1
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}
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// Evaluate the test start index and number of tests to run
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startIndex = numPrecedingMaxLoadNodes*maxTestsPerNode + numPrecedingMinLoadNodes*minTestsPerNode
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if parallelNode > numMaxLoadNodes {
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count = minTestsPerNode
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} else {
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count = maxTestsPerNode
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}
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return
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}
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