first pass at safe_power() engine fn

.github/workflows/R-CMD-check.yaml

@@ -30,7 +30,7 @@ jobs:
       R_REMOTES_NO_ERRORS_FROM_WARNINGS: true
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - uses: r-lib/actions/setup-pandoc@v2
 

.github/workflows/pkgdown.yaml

@@ -18,7 +18,7 @@ jobs:
     env:
       GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - uses: r-lib/actions/setup-pandoc@v2
 

.github/workflows/test-coverage.yaml

@@ -13,7 +13,7 @@ jobs:
       GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - uses: r-lib/actions/setup-r@v2
         with:

R/engine_functions.R

@@ -816,4 +816,5 @@
 #' @aliases reulermultinom
 #' @aliases round
 #' @aliases pgamma
+#' @aliases safe_power
 NULL

R/enum.R

@@ -50,6 +50,7 @@ valid_func_sigs = c(
       , "fwrap,fail: reulermultinom(size, rate, delta_t)"
       , "fwrap,null: round(x)"
       , "fwrap,fail: pgamma(q, shape, scale)"
+      , "fwrap,fail: safe_power(x,y)"
 )
 process_enum = function(x) {
   RE = "(null|fail|binop|fwrap|bwrap|pwrap)[ ]*,[ ]*(null|fail|binop|fwrap|bwrap|pwrap)[ ]*:[ ]*\\`?([^`]*)\\`?\\((.*)(\\,.*)*\\)"

misc/dev/dev.cpp

@@ -111,6 +111,7 @@ enum macpan2_func
     , MP2_EULER_MULTINOM_SIM = 48 // fwrap,fail: reulermultinom(size, rate, delta_t)
     , MP2_ROUND = 49 // fwrap,null: round(x)
     , MP2_PGAMMA = 50 // fwrap,fail: pgamma(q, shape, scale)
+    , MP2_SAFEPOWER = 51 // fwrap,fail: safe_power(x,y)
 };
 
 enum macpan2_meth
@@ -1286,6 +1287,41 @@ class ExprEvaluator
                 #endif
                 return pow(args[0].array(), args[1].array()).matrix();
                 // return args[0].pow(args[1].coeff(0,0));
+
+            case MP2_SAFEPOWER: // SAFE_POWER, equivalent to (ifelse(x==0, 0, x^y))
+                if (n != 2) {
+                    SetError(err_code, "safe_power requires exactly two arguments", row, table_x[row] + 1, args.all_rows(), args.all_cols(), args.all_type_ints());
+                    return m;
+                }
+                args = args.recycle_for_bin_op();
+                err_code = args.get_error_code();
+                switch (err_code) {
+                    case 201:
+                        SetError(err_code, "The two operands do not have the same number of columns", row, table_x[row] + 1, args.all_rows(), args.all_cols(), args.all_type_ints());
+                        return m;
+                    case 202:
+                        SetError(err_code, "The two operands do not have the same number of rows", row, table_x[row] + 1, args.all_rows(), args.all_cols(), args.all_type_ints());
+                        return m;
+                    case 203:
+                        SetError(err_code, "The two operands do not have the same number of columns or rows", row, table_x[row] + 1, args.all_rows(), args.all_cols(), args.all_type_ints());
+                        return m;
+                }
+                m1 = args[0];
+                m2 = args[1];
+                rows = m1.rows();
+                cols = m1.cols();
+                m = matrix<Type>::Zero(rows, cols);
+                for (int i = 0; i < rows; i++) {
+                    for (int j = 0; j < cols; j++) {
+                        m.coeffRef(i, j) = CppAD::CondExpEq(
+                            m1.coeff(i, j), 
+                            Type(0), 
+                            Type(0), 
+                            pow(m1.coeff(i, j), m2.coeff(i, j))
+                        );
+                    }
+                }
+                return m;
 
             // #' ## Unary Elementwise Math
             // #'

src/macpan2.cpp

@@ -112,6 +112,7 @@ enum macpan2_func
     , MP2_EULER_MULTINOM_SIM = 48 // fwrap,fail: reulermultinom(size, rate, delta_t)
     , MP2_ROUND = 49 // fwrap,null: round(x)
     , MP2_PGAMMA = 50 // fwrap,fail: pgamma(q, shape, scale)
+    , MP2_SAFEPOWER = 51 // fwrap,fail: safe_power(x,y)
 };
 
 enum macpan2_meth
@@ -1287,6 +1288,41 @@ class ExprEvaluator
                 #endif
                 return pow(args[0].array(), args[1].array()).matrix();
                 // return args[0].pow(args[1].coeff(0,0));
+
+            case MP2_SAFEPOWER: // SAFE_POWER, equivalent to (ifelse(x==0, 0, x^y))
+                if (n != 2) {
+                    SetError(err_code, "safe_power requires exactly two arguments", row, table_x[row] + 1, args.all_rows(), args.all_cols(), args.all_type_ints());
+                    return m;
+                }
+                args = args.recycle_for_bin_op();
+                err_code = args.get_error_code();
+                switch (err_code) {
+                    case 201:
+                        SetError(err_code, "The two operands do not have the same number of columns", row, table_x[row] + 1, args.all_rows(), args.all_cols(), args.all_type_ints());
+                        return m;
+                    case 202:
+                        SetError(err_code, "The two operands do not have the same number of rows", row, table_x[row] + 1, args.all_rows(), args.all_cols(), args.all_type_ints());
+                        return m;
+                    case 203:
+                        SetError(err_code, "The two operands do not have the same number of columns or rows", row, table_x[row] + 1, args.all_rows(), args.all_cols(), args.all_type_ints());
+                        return m;
+                }
+                m1 = args[0];
+                m2 = args[1];
+                rows = m1.rows();
+                cols = m1.cols();
+                m = matrix<Type>::Zero(rows, cols);
+                for (int i = 0; i < rows; i++) {
+                    for (int j = 0; j < cols; j++) {
+                        m.coeffRef(i, j) = CppAD::CondExpEq(
+                            m1.coeff(i, j), 
+                            Type(0), 
+                            Type(0), 
+                            pow(m1.coeff(i, j), m2.coeff(i, j))
+                        );
+                    }
+                }
+                return m;
 
             // #' ## Unary Elementwise Math
             // #'

tests/testthat/test-binop.R

@@ -1,3 +1,5 @@
+library(macpan2); library(testthat); library(dplyr); library(tidyr); library(ggplot2)
+
 test_that("elementwise binary operator executable specs match spec doc", {
   ## https://canmod.net/misc/elementwise_binary_operators
   times = BinaryOperator(`*`)
@@ -83,3 +85,30 @@ test_that("elementwise binary operator executable specs match spec doc", {
 test_that("equivalent unary and binary minus operators give the same answers", {
   expect_equal(engine_eval(~-4), engine_eval(~0-4))
 })
+
+test_that("safe_power meets the requirements of #200", {
+  expect_equal(
+    matrix(0.1 ^ -5),
+    engine_eval(~safe_power(0.1, -5))
+  )
+  expect_equal(
+    matrix(0 ^ 5),
+    engine_eval(~safe_power(0, 5))
+  )
+  expect_equal(
+    matrix(c(1, 1, 0, 1, 1)), # != matrix((-2:2)^0),
+    engine_eval(~safe_power(-2:2, 0))
+  )
+  expect_equal(
+    matrix(rep(0, 5)), # != matrix(0^(-2:2))
+    engine_eval(~safe_power(0, -2:2))
+  )
+  expect_error(
+    engine_eval(~safe_power(1)),
+    regexp = "safe_power requires exactly two arguments"
+  )
+  expect_error(
+    engine_eval(~safe_power(1:3, 2:3)),
+    regexp = "The two operands do not have the same number of rows"
+  )
+})