/*******************************************************************************
 * Copyright (c) 2015-2018 Skymind, Inc.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Apache License, Version 2.0 which is available at
 * https://www.apache.org/licenses/LICENSE-2.0.
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 * SPDX-License-Identifier: Apache-2.0
 ******************************************************************************/

//
// @author Yurii Shyrma (iuriish@yahoo.com)
//

#include <op_boilerplate.h>
#if NOT_EXCLUDED(OP_polygamma)

#include <ops/declarable/CustomOperations.h>
#include <ops/declarable/helpers/gammaMathFunc.h>

namespace nd4j {
namespace ops  {

CONFIGURABLE_OP_IMPL(polygamma, 2, 1, false, 0, 0) {
    auto n = INPUT_VARIABLE(0);
    auto x = INPUT_VARIABLE(1);

    auto output   = OUTPUT_VARIABLE(0);

    REQUIRE_TRUE(n->isSameShape(x), 0, "POLYGAMMA op: two input arrays n and x must have the same shapes, but got n=%s and x=%s instead !", ShapeUtils::shapeAsString(n).c_str(), ShapeUtils::shapeAsString(x).c_str());

    Nd4jLong arrLen = n->lengthOf();
    // FIXME: this shit should be single op call, not a loop!
    auto nNegative = n->reduceNumber(nd4j::reduce::IsNegative, nullptr);
    auto xPositive = x->reduceNumber(nd4j::reduce::IsPositive, nullptr);
    bool nPositiveFlag = !nNegative.e<bool>(0);                             // require all n >= 0
    bool xPositiveFlag = xPositive.e<bool>(0);                              // require all x > 0
    REQUIRE_TRUE(nPositiveFlag, 0, "POLYGAMMA op: all elements of n array must be >= 0 !");
    REQUIRE_TRUE(xPositiveFlag, 0, "POLYGAMMA op: all elements of x array must be > 0 !");

    helpers::polyGamma(block.launchContext(), *n, *x, *output);
    return Status::OK();
}

DECLARE_SYN(polyGamma, polygamma);
DECLARE_SYN(PolyGamma, polygamma);

    DECLARE_TYPES(polygamma) {
        getOpDescriptor()
                ->setAllowedInputTypes({ALL_FLOATS})
                ->setSameMode(true);
    }
}
}

#endif