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#include "NTensor.hh"
#include <stdexcept>
#include "Stopwatch.hh"
#include <cassert>
#include <cmath>
using namespace cadabra;
NTensor::NTensor(const std::vector<size_t>& shape_, double val)
: shape(shape_)
{
size_t len=1;
for(auto dim: shape)
len *= dim;
values.resize(len);
for(auto& v: values)
v=val;
}
NTensor::NTensor(const std::vector<double>& vals)
: values(vals)
{
shape.push_back(values.size());
}
NTensor::NTensor(double val)
{
values.push_back(val);
shape.push_back(1);
}
NTensor::NTensor(const NTensor& other)
{
shape=other.shape;
values=other.values;
}
NTensor NTensor::linspace(double from, double to, size_t steps)
{
NTensor res(std::vector<size_t>({steps}), 0.0);
assert(steps>1);
for(size_t i=0; i<steps; ++i) {
res.values[i] = from + i*(to-from)/(steps-1);
}
return res;
}
NTensor& NTensor::operator=(const NTensor& other)
{
shape=other.shape;
values=other.values;
return *this;
}
double NTensor::at(const std::vector<size_t>& indices) const
{
if(indices.size()!=shape.size())
throw std::range_error("NTensor::at: number of indices != shape length.");
size_t idx = 0;
size_t stride=1;
for(size_t p=indices.size(); p-- != 0; ) {
if(indices[p]>=shape[p])
throw std::range_error("NTensor::at: index out of range.");
idx += stride*indices[p];
stride *= shape[p];
}
if(idx >= values.size())
throw std::range_error("NTensor::at: indices out of range.");
return values[idx];
}
double& NTensor::at(const std::vector<size_t>& indices)
{
if(indices.size()!=shape.size())
throw std::range_error("NTensor::at: number of indices != shape length.");
size_t idx = 0;
size_t stride=1;
for(size_t p=indices.size(); p-- != 0; ) {
if(indices[p]>=shape[p])
throw std::range_error("NTensor::at: index out of range.");
idx += stride*indices[p];
stride *= shape[p];
}
if(idx >= values.size())
throw std::range_error("NTensor::at: indices out of range.");
return values[idx];
}
std::ostream& operator<<(std::ostream &str, const NTensor &nt)
{
// For an {a,b} tensor, we display as a vector of size 'a', each
// element of which is a vector of size 'b'. And so on.
for(size_t p=0; p<nt.shape.size(); ++p)
str << "[";
for(size_t i=0; i<nt.values.size(); ++i) {
str << nt.values[i];
// Closing/re-opening.
size_t mult=1;
for(size_t p=nt.shape.size(); p-- != 0; ) {
// 2,4,3 -> 2, 8, 24
mult *= nt.shape[p];
if((i+1)%mult == 0)
str << "]";
}
if(i+1<nt.values.size()) {
str << ", ";
mult=1;
for(size_t p=nt.shape.size(); p-- != 0; ) {
mult *= nt.shape[p];
if((i+1)%mult == 0)
str << "[";
}
}
}
return str;
}
NTensor& NTensor::apply(double (*fun)(double))
{
for(auto& v: values)
v = fun(v);
return *this;
}
NTensor& NTensor::operator+=(const NTensor& other)
{
if(other.shape.size()==1 && other.shape[0]==1) {
// Arbitrary size base to the power of a scalar.
for(size_t i=0; i<values.size(); ++i)
values[i] += other.values[0];
}
else {
if(shape.size() != other.shape.size())
throw std::range_error("NTensor::pow: shape lengths do not match.");
for(size_t p=0; p<shape.size(); ++p)
if(shape[p]!=other.shape[p])
throw std::range_error("NTensor::operator+=: shapes do not match.");
for(size_t i=0; i<values.size(); ++i)
values[i] += other.values[i];
}
return *this;
}
NTensor& NTensor::operator*=(const NTensor& other)
{
if(other.shape.size()==1 && other.shape[0]==1) {
// Arbitrary size base to the power of a scalar.
for(size_t i=0; i<values.size(); ++i)
values[i] *= other.values[0];
}
else {
if(shape.size() != other.shape.size())
throw std::range_error("NTensor::pow: shape lengths do not match.");
for(size_t p=0; p<shape.size(); ++p)
if(shape[p]!=other.shape[p])
throw std::range_error("NTensor::operator+=: shapes do not match.");
for(size_t i=0; i<values.size(); ++i)
values[i] *= other.values[i];
}
return *this;
}
NTensor& NTensor::pow(const NTensor& other)
{
if(other.shape.size()==1 && other.shape[0]==1) {
// Arbitrary size base to the power of a scalar.
for(size_t i=0; i<values.size(); ++i)
values[i] = std::pow(values[i], other.values[0]);
}
else {
if(shape.size() != other.shape.size())
throw std::range_error("NTensor::pow: shape lengths do not match.");
for(size_t p=0; p<shape.size(); ++p)
if(shape[p]!=other.shape[p])
throw std::range_error("NTensor::pow: shapes do not match; direction "
+std::to_string(p)+": "
+std::to_string(shape[p])+" vs. "
+std::to_string(other.shape[p])+".");
for(size_t i=0; i<values.size(); ++i)
values[i] = std::pow(values[i], other.values[i]);
}
return *this;
}
NTensor NTensor::outer_product(const NTensor& a, const NTensor& b)
{
// std::cerr << "multiplying " << a << "\n"
// << " with " << b << std::endl;
std::vector<size_t> res_shape;
res_shape.insert(res_shape.end(), a.shape.begin(), a.shape.end());
res_shape.insert(res_shape.end(), b.shape.begin(), b.shape.end());
NTensor res( res_shape, 0.0 );
for(size_t i=0; i<res.values.size(); ++i) {
size_t idx_a = i / b.values.size();
size_t idx_b = i % b.values.size();
assert(idx_a < a.values.size());
assert(idx_b < b.values.size());
res.values[i] = a.values[idx_a] * b.values[idx_b];
}
return res;
}
NTensor NTensor::broadcast(std::vector<size_t> new_shape, size_t pos) const
{
// for(auto s: new_shape)
// std::cerr << s << ", ";
// std::cerr << "\n" << pos << std::endl;
assert( pos < new_shape.size() );
assert( shape.size()==1 );
assert( new_shape[pos]==shape[0] );
NTensor res(new_shape, 0.);
size_t lower = 1, higher=1;
for(size_t s=pos+1; s<new_shape.size(); ++s)
lower *= new_shape[s];
higher = lower * new_shape[pos];
// std::cerr << "lower: " << lower << "\nhigher: " << higher << std::endl;
// Stopwatch sw;
// sw.start();
for(size_t i=0; i<res.values.size(); ++i) {
size_t orig_i = (i % higher) / lower;
// std::cerr << i << " -> " << orig_i << std::endl;
assert( orig_i < new_shape[pos] );
res.values[i] = values[orig_i];
}
// sw.stop();
// std::cerr << "broadcast to " << res.values.size() << " took " << sw << std::endl;
return res;
}
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