alexbrandmeyer@609: //
alexbrandmeyer@609: //  carfac_common.h
alexbrandmeyer@609: //  CARFAC Open Source C++ Library
alexbrandmeyer@609: //
alexbrandmeyer@609: //  Created by Alex Brandmeyer on 5/10/13.
alexbrandmeyer@609: //
alexbrandmeyer@609: // This C++ file is part of an implementation of Lyon's cochlear model:
alexbrandmeyer@609: // "Cascade of Asymmetric Resonators with Fast-Acting Compression"
alexbrandmeyer@609: // to supplement Lyon's upcoming book "Human and Machine Hearing"
alexbrandmeyer@609: //
alexbrandmeyer@609: // Licensed under the Apache License, Version 2.0 (the "License");
alexbrandmeyer@609: // you may not use this file except in compliance with the License.
alexbrandmeyer@609: // You may obtain a copy of the License at
alexbrandmeyer@609: //
alexbrandmeyer@609: //     http://www.apache.org/licenses/LICENSE-2.0
alexbrandmeyer@609: //
alexbrandmeyer@609: // Unless required by applicable law or agreed to in writing, software
alexbrandmeyer@609: // distributed under the License is distributed on an "AS IS" BASIS,
alexbrandmeyer@609: // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
alexbrandmeyer@609: // See the License for the specific language governing permissions and
alexbrandmeyer@609: // limitations under the License.
alexbrandmeyer@609: //
alexbrandmeyer@609: // *****************************************************************************
alexbrandmeyer@609: // carfac_common.h
alexbrandmeyer@609: // *****************************************************************************
alexbrandmeyer@609: // This file contains the base level definitions and includes used within the
alexbrandmeyer@609: // CARFAC C++ library. It also defines some low level functions which are used
alexbrandmeyer@609: // during the calculation of the various coefficient sets required by the model.
alexbrandmeyer@609: //
alexbrandmeyer@609: // The current implementation of the library is dependent on the use of the
alexbrandmeyer@609: // Eigen C++ library for linear algebra. Specifically, Eigen Arrays are used
alexbrandmeyer@609: // extensively for coefficient wise operations during both the design and run
alexbrandmeyer@609: // stages of the model.
alexbrandmeyer@609: //
alexbrandmeyer@609: // The 'FPType' typedef is specified in this file in order to enable quick
alexbrandmeyer@609: // switching between precision levels (i.e. float vs. double) throughout the
alexbrandmeyer@609: // library. The remainder of the code uses this type for specifying floating
alexbrandmeyer@609: // point scalars.
alexbrandmeyer@609: //
alexbrandmeyer@609: // Two additional typedefs are defined for one and two dimensional arrays:
alexbrandmeyer@609: // FloatArray and FloatArray2d. These in turn make use of FPType so that the
alexbrandmeyer@609: // precision level across floating point data is consistent.
alexbrandmeyer@609: //
alexbrandmeyer@609: // The functions 'ERBHz' and 'CARFACDetect' are defined here, and are used
alexbrandmeyer@609: // during the design stage of a CARFAC model. 
alexbrandmeyer@609: 
alexbrandmeyer@609: #ifndef CARFAC_Open_Source_C__Library_CARFACCommon_h
alexbrandmeyer@609: #define CARFAC_Open_Source_C__Library_CARFACCommon_h
alexbrandmeyer@609: 
alexbrandmeyer@610: // This section is where the base include operations for the CARFAC project
alexbrandmeyer@610: // occur.
alexbrandmeyer@610: // <iostream> is used for debugging output, but it could go in final version.
alexbrandmeyer@610: #include <iostream>
alexbrandmeyer@610: // <math.h> is used during coefficient calculations and runtime operations.
alexbrandmeyer@610: #include <math.h>
alexbrandmeyer@610: // <vector> is used in place of 2d Eigen Arrays for the AGC memory
alexbrandmeyer@610: #include <vector>
alexbrandmeyer@610: // The Eigen library is used extensively for 1d and 2d floating point arrays.
alexbrandmeyer@610: // For more information, see: http://eigen.tuxfamily.org
alexbrandmeyer@610: #include <Eigen/Dense>
alexbrandmeyer@609: using namespace Eigen;
alexbrandmeyer@609: 
alexbrandmeyer@610: // One constant value is defined here, but see my TODO regarding style issues.
alexbrandmeyer@610: // A fixed value of PI is defined throughout the project.
alexbrandmeyer@610: // TODO alexbrandmeyer: verify that this is OK with Google Style.
alexbrandmeyer@610: #define PI 3.141592653589793238
alexbrandmeyer@609: 
alexbrandmeyer@610: // Three typedefs are used for enabling quick switching of precision and array
alexbrandmeyer@610: // usage. 
alexbrandmeyer@610: // The 'FPType' typedef is used to enable easy switching in precision level.
alexbrandmeyer@610: typedef double FPType;
alexbrandmeyer@610: // These are the two typedefs for Eigen floating point arrays.
alexbrandmeyer@610: typedef Eigen::Array<FPType, Dynamic, 1> FloatArray;  // This is a 1d array.
alexbrandmeyer@610: typedef Eigen::Array<FPType, Dynamic, Dynamic> FloatArray2d;  // This is 2d.
alexbrandmeyer@610: 
alexbrandmeyer@610: // Two psychoacoustics helper functions are defined here for use by the
alexbrandmeyer@610: // different processing stages in calculating coeffecients.
alexbrandmeyer@609: 
alexbrandmeyer@609: // Function: ERBHz
alexbrandmeyer@609: // Auditory filter nominal Equivalent Rectangular Bandwidth
alexbrandmeyer@609: // Ref: Glasberg and Moore: Hearing Research, 47 (1990), 103-138
alexbrandmeyer@609: FPType ERBHz(FPType cf_hz, FPType erb_break_freq, FPType erb_q);
alexbrandmeyer@609: 
alexbrandmeyer@609: // Function CARFACDetect
alexbrandmeyer@609: // TODO explain a bit more
alexbrandmeyer@609: FloatArray CARFACDetect (FloatArray x);
alexbrandmeyer@610: 
alexbrandmeyer@610: #endif