The Tensor Algebra Compiler (taco) computes tensor expressions on sparse and dense tensors
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The Tensor Algebra Compiler (taco) is a C++ library that computes tensor algebra expressions on sparse and dense tensors. It uses novel compiler techniques to get performance competitive with hand-optimized kernels in widely used libraries for both sparse tensor algebra and sparse linear algebra.

You can use taco as a C++ library that lets you load tensors, read tensors from files, and compute tensor expressions. You can also use taco as a code generator that generates C functions that compute tensor expressions.

Learn more about taco at, in the paper The Tensor Algebra Compiler, or in this talk. To learn more about where taco is going in the near-term, see the technical reports on optimization and formats.

You can also subscribe to the taco-announcements email list where we post announcements, RFCs, and notifications of API changes, or the taco-discuss email list for open discussions and questions.

TL;DR build taco using cmake. Run taco-test in the bin directory.

Build and test

Build taco using CMake 2.8.3 or greater:

cd <taco-directory>
mkdir build
cd build
cmake -DCMAKE_BUILD_TYPE=Release ..
make -j8

Run the test suite:

cd <taco-directory>

Library Example

The following sparse tensor-times-vector multiplication example in C++ shows how to use the taco library.

// Create formats
Format csr({Dense,Sparse});
Format csf({Sparse,Sparse,Sparse});
Format  sv({Sparse});

// Create tensors
Tensor<double> A({2,3},   csr);
Tensor<double> B({2,3,4}, csf);
Tensor<double> c({4},     sv);

// Insert data into B and c
B.insert({0,0,0}, 1.0);
B.insert({1,2,0}, 2.0);
B.insert({1,3,1}, 3.0);
c.insert({0}, 4.0);
c.insert({1}, 5.0);

// Pack inserted data as described by the formats

// Form a tensor-vector multiplication expression
IndexVar i, j, k;
A(i,j) = B(i,j,k) * c(k);

// Compile the expression

// Assemble A's indices and numerically compute the result

std::cout << A << std::endl;

Code generation tools

If you just need to compute a single tensor kernel you can use the taco online tool to generate a custom C library. You can also use the taco command-line tool to the same effect:

cd <taco-directory>
Usage: taco [options] <index expression>

  taco "a(i) = b(i) + c(i)"                            # Dense vector add
  taco "a(i) = b(i) + c(i)" -f=b:s -f=c:s -f=a:s       # Sparse vector add
  taco "a(i) = B(i,j) * c(j)" -f=B:ds                  # SpMV
  taco "A(i,l) = B(i,j,k) * C(j,l) * D(k,l)" -f=B:sss  # MTTKRP


For more information, see our paper on the taco tools taco: A Tool to Generate Tensor Algebra Kernels.