Custom base for decoding ADC data (#163)

New function apply_custom_weights (can we find a better name) that takes
a uint16 and a NDView<double,1> of bases for the conversion. For each
supplied weight it is used as base (instead of 2) to convert from bits
to a double.

---------

Co-authored-by: siebsi <sieb.patr@gmail.com>

src/NDView.test.cpp

@@ -190,4 +190,16 @@ TEST_CASE("compare two views") {
     NDView<int, 2> view2(vec2.data(), Shape<2>{3, 4});
 
     REQUIRE((view1 == view2));
+}
+
+
+TEST_CASE("Create a view over a vector"){
+    std::vector<int> vec;
+    for (int i = 0; i != 12; ++i) {
+        vec.push_back(i);
+    }
+    auto v = aare::make_view(vec);
+    REQUIRE(v.shape()[0] == 12);
+    REQUIRE(v[0] == 0);
+    REQUIRE(v[11] == 11);
 }

src/decode.cpp

@@ -1,5 +1,5 @@
 #include "aare/decode.hpp"
-
+#include <cmath>
 namespace aare {
 
 uint16_t adc_sar_05_decode64to16(uint64_t input){
@@ -22,6 +22,10 @@ uint16_t adc_sar_05_decode64to16(uint64_t input){
 }
 
 void adc_sar_05_decode64to16(NDView<uint64_t, 2> input, NDView<uint16_t,2> output){
+    if(input.shape() != output.shape()){
+        throw std::invalid_argument(LOCATION + " input and output shapes must match");
+    }
+
     for(int64_t i = 0; i < input.shape(0); i++){
         for(int64_t j = 0; j < input.shape(1); j++){
             output(i,j) = adc_sar_05_decode64to16(input(i,j));
@@ -49,6 +53,9 @@ uint16_t adc_sar_04_decode64to16(uint64_t input){
 }
 
 void adc_sar_04_decode64to16(NDView<uint64_t, 2> input, NDView<uint16_t,2> output){
+    if(input.shape() != output.shape()){
+        throw std::invalid_argument(LOCATION + " input and output shapes must match");
+    }
     for(int64_t i = 0; i < input.shape(0); i++){
         for(int64_t j = 0; j < input.shape(1); j++){
             output(i,j) = adc_sar_04_decode64to16(input(i,j));
@@ -56,6 +63,40 @@ void adc_sar_04_decode64to16(NDView<uint64_t, 2> input, NDView<uint16_t,2> outpu
     }
 }
 
+double apply_custom_weights(uint16_t input, const NDView<double, 1> weights) {
+    if(weights.size() > 16){
+        throw std::invalid_argument("weights size must be less than or equal to 16");
+    }
+
+    double result = 0.0;
+    for (ssize_t i = 0; i < weights.size(); ++i) {
+        result += ((input >> i) & 1) * std::pow(weights[i], i);
+    }
+    return result;
+
+}
+
+void apply_custom_weights(NDView<uint16_t, 1> input, NDView<double, 1> output, const NDView<double,1> weights) {
+    if(input.shape() != output.shape()){
+        throw std::invalid_argument(LOCATION + " input and output shapes must match");
+    }
+
+    //Calculate weights to avoid repeatedly calling std::pow
+    std::vector<double> weights_powers(weights.size());
+    for (ssize_t i = 0; i < weights.size(); ++i) {
+        weights_powers[i] = std::pow(weights[i], i);
+    }
+
+    // Apply custom weights to each element in the input array
+    for (ssize_t i = 0; i < input.shape(0); i++) {            
+        double result = 0.0;
+        for (size_t bit_index = 0; bit_index < weights_powers.size(); ++bit_index) {
+            result += ((input(i) >> bit_index) & 1) * weights_powers[bit_index];
+        }
+        output(i) = result;
+    }
+}
+
 
 
 } // namespace aare

src/decode.test.cpp

@@ -0,0 +1,80 @@
+#include "aare/decode.hpp"
+
+#include <catch2/matchers/catch_matchers_floating_point.hpp>
+#include <catch2/catch_test_macros.hpp>
+#include "aare/NDArray.hpp"
+using Catch::Matchers::WithinAbs;
+#include <vector>
+
+TEST_CASE("test_adc_sar_05_decode64to16"){
+    uint64_t input = 0;
+    uint16_t output = aare::adc_sar_05_decode64to16(input);
+    CHECK(output == 0);
+
+
+    // bit 29 on th input is bit 0 on the output
+    input = 1UL << 29;
+    output = aare::adc_sar_05_decode64to16(input);
+    CHECK(output == 1);
+
+    // test all bits by iteratting through the bitlist
+    std::vector<int> bitlist = {29, 19, 28, 18, 31, 21, 27, 20, 24, 23, 25, 22};
+    for (size_t i = 0; i < bitlist.size(); i++) {
+        input = 1UL << bitlist[i];
+        output = aare::adc_sar_05_decode64to16(input);
+        CHECK(output == (1 << i));
+    }
+
+    
+    // test a few "random" values
+    input = 0;
+    input |= (1UL << 29);
+    input |= (1UL << 19);
+    input |= (1UL << 28);
+    output = aare::adc_sar_05_decode64to16(input);
+    CHECK(output == 7UL);
+
+
+    input = 0;
+    input |= (1UL << 18);
+    input |= (1UL << 27);
+    input |= (1UL << 25);
+    output = aare::adc_sar_05_decode64to16(input);
+    CHECK(output == 1096UL);
+
+    input = 0;
+    input |= (1UL << 25);
+    input |= (1UL << 22);
+    output = aare::adc_sar_05_decode64to16(input);
+    CHECK(output == 3072UL);
+ }
+
+
+ TEST_CASE("test_apply_custom_weights") {
+
+    uint16_t input = 1;
+    aare::NDArray<double, 1> weights_data({3}, 0.0);
+    weights_data(0) = 1.7;
+    weights_data(1) = 2.1;
+    weights_data(2) = 1.8;
+
+    auto weights = weights_data.view();
+
+
+    double output = aare::apply_custom_weights(input, weights);
+    CHECK_THAT(output, WithinAbs(1.0, 0.001));
+
+    input = 1UL << 1;
+    output = aare::apply_custom_weights(input, weights);
+    CHECK_THAT(output, WithinAbs(2.1, 0.001));
+
+
+    input = 1UL << 2;
+    output = aare::apply_custom_weights(input, weights);
+    CHECK_THAT(output, WithinAbs(3.24, 0.001));
+
+    input = 0b111;
+    output = aare::apply_custom_weights(input, weights);
+    CHECK_THAT(output, WithinAbs(6.34, 0.001));
+
+ }