onnxruntime

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// Copyright (c) Microsoft Corporation. All rights reserved.
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// Licensed under the MIT License.
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import { DataType } from '../../../wasm-common';
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import { TensorView } from '../../tensor-view';
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import { ShapeUtil } from '../../util';
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import { AttributeWithCacheKey, createAttributeWithCacheKey } from '../attribute-with-cache-key';
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import { ComputeContext, ProgramInfo, ProgramUniform } from '../types';
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import { createTensorShapeVariables, inputVariable, outputVariable, ShaderHelper } from './common';
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export interface GatherAttributes extends AttributeWithCacheKey {
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  axis: number;
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}
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const validateInputs = (inputs: readonly TensorView[]): void => {
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  if (!inputs || inputs.length !== 2) {
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    throw new Error('Gather requires 2 inputs.');
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  }
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};
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const createGatherProgramInfo = (inputs: readonly TensorView[], attributes: GatherAttributes): ProgramInfo => {
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  const inputShape = inputs[0].dims;
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  const indicesShape = inputs[1].dims;
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  const inputRank = inputShape.length;
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  const axis = ShapeUtil.normalizeAxis(attributes.axis, inputRank);
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  const outputShape = inputShape.slice(0);
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  outputShape.splice(axis, 1, ...indicesShape);
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  const axisDimLimit = inputShape[axis];
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  const components = inputs[0].dataType === DataType.bool ? 4 : 1;
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  const outputSize = Math.ceil(ShapeUtil.size(outputShape) / components);
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  const programUniforms: ProgramUniform[] = [
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    { type: DataType.uint32, data: outputSize },
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    { type: DataType.int32, data: axisDimLimit },
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    { type: DataType.uint32, data: axis },
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    ...createTensorShapeVariables(inputs[0].dims, inputs[1].dims, outputShape),
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  ];
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  const getShaderSource = (shaderHelper: ShaderHelper) => {
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    const data = inputVariable('data', inputs[0].dataType, inputs[0].dims.length, components);
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    const indices = inputVariable('inputIndices', inputs[1].dataType, inputs[1].dims.length);
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    const output = outputVariable('output', inputs[0].dataType, outputShape.length, components);
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    const calcDataIndices = (x: number | string): string => {
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      const indicesRank = indicesShape.length;
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      let calcStr = `var indicesIndices${x}  = ${indices.type.indices}(0);`;
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      for (let i = 0; i < indicesRank; i++) {
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        calcStr += `${indicesRank > 1 ? `indicesIndices${x}[${i}]` : `indicesIndices${x}`} = ${
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          outputShape.length > 1 ? `outputIndices${x}[uniforms.axis + ${i}]` : `outputIndices${x}`
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        };`;
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      }
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      calcStr += `
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          var idx${x} = ${indices.getByIndices(`indicesIndices${x}`)};
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          if (idx${x} < 0) {
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            idx${x} = idx${x} + uniforms.axisDimLimit;
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          }
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          var dataIndices${x} : ${data.type.indices};
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        `;
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      for (let i = 0, j = 0; i < inputRank; i++) {
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        if (i === axis) {
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          calcStr += `${inputRank > 1 ? `dataIndices${x}[${i}]` : `dataIndices${x}`} = u32(idx${x});`;
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          j += indicesRank;
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        } else {
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          calcStr += `${inputRank > 1 ? `dataIndices${x}[${i}]` : `dataIndices${x}`} = ${
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            outputShape.length > 1 ? `outputIndices${x}[${j}]` : `outputIndices${x}`
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          };`;
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          j++;
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        }
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      }
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      return calcStr;
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    };
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    let assignment: string;
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    if (inputs[0].dataType === DataType.bool) {
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      const singleAssignment = (resStr: string, x: number, typeCast = '') => `
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          let outputIndices${x} = ${output.offsetToIndices(`outputOffset + ${x}u`)};
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          ${calcDataIndices(x)};
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          let offset${x} = ${data.indicesToOffset(`dataIndices${x}`)};
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          let index${x} = offset${x} / 4u;
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          let component${x} = offset${x} % 4u;
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          ${resStr}[${x}] = ${typeCast}(${data.getByOffset(`index${x}`)}[component${x}]);
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        `;
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      assignment = `
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        let outputOffset = global_idx * ${components};
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        var value = vec4<u32>(0);
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        ${singleAssignment('value', 0, 'u32')}
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        ${singleAssignment('value', 1, 'u32')}
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        ${singleAssignment('value', 2, 'u32')}
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        ${singleAssignment('value', 3, 'u32')}
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        ${output.setByOffset('global_idx', 'value')}
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      `;
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    } else {
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      assignment = `
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      let outputIndices = ${output.offsetToIndices('global_idx')};
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      ${calcDataIndices('')};
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      let value = ${data.getByIndices('dataIndices')};
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      ${output.setByOffset('global_idx', 'value')};
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      `;
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    }
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    return `
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      ${shaderHelper
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        .registerUniform('outputSize', 'u32')
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        .registerUniform('axisDimLimit', 'i32')
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        .registerUniform('axis', 'u32')
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        .declareVariables(data, indices, output)}
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      ${shaderHelper.mainStart()}
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        ${shaderHelper.guardAgainstOutOfBoundsWorkgroupSizes('uniforms.outputSize')}
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        ${assignment}
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      }`;
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  };
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  return {
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    name: 'Gather',
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    shaderCache: { hint: attributes.cacheKey, inputDependencies: ['rank', 'rank'] },
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    getRunData: () => ({
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      outputs: [{ dims: outputShape, dataType: inputs[0].dataType }],
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      dispatchGroup: { x: Math.ceil(outputSize / 64 /* workgroup size */) },
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      programUniforms,
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    }),
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    getShaderSource,
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  };
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};
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export const parseGatherAttributes = (attributes: Record<string, unknown>): GatherAttributes =>
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  createAttributeWithCacheKey({ axis: attributes.axis as number });
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export const gather = (context: ComputeContext, attributes: GatherAttributes): void => {
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  const inputs = context.inputs;
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  validateInputs(inputs);
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  context.compute(createGatherProgramInfo(context.inputs, attributes));
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};
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