Added std, var and corr operations.

ibis/mapd/api.py

@@ -1,6 +1,7 @@
 from ibis.config import options
 from ibis.mapd.compiler import dialect, compiles, rewrites
 from ibis.mapd.client import MapDClient
+from ibis.mapd.operations import pi
 
 import ibis.common as com
 

ibis/mapd/compiler.py

@@ -3,10 +3,11 @@
 import ibis.common as com
 import ibis.util as util
 import ibis.expr.operations as ops
+import ibis.expr.types as ir
 import ibis.sql.compiler as compiles
 
 from .operations import (
-    _operation_registry, _name_expr, _trigonometric_ops
+    _operation_registry, _name_expr, Corr
 )
 
 
@@ -194,3 +195,60 @@ class MapDDialect(compiles.Dialect):
 dialect = MapDDialect
 compiles = MapDExprTranslator.compiles
 rewrites = MapDExprTranslator.rewrites
+
+
+@compiles(ops.StandardDev)
+def compile_std(translator, expr):
+    # pull out the arguments to the expression
+    args = expr.op().args
+    args_size = len(args)
+
+    x = args[0]
+    how = '' if args_size < 2 else '_%s' % args[1].upper()[:4]
+
+    f_type = '' if isinstance(x, ir.IntegerColumn) else '_FLOAT'
+
+    # compile the argument
+    compiled_arg = translator.translate(x)
+
+    return 'STDDEV%s%s(%s)' % (how, f_type, compiled_arg)
+
+
+@compiles(ops.Variance)
+def compile_var(translator, expr):
+    # pull out the arguments to the expression
+    args = expr.op().args
+    args_size = len(args)
+
+    x = args[0]
+    how = '' if args_size < 2 else '_%s' % args[1].upper()[:4]
+
+    if how == '':
+        f_name = 'VARIANCE'
+    else:
+        f_name = 'VAR'
+
+    f_type = '' if isinstance(x, ir.IntegerColumn) else '_FLOAT'
+
+    # compile the argument
+    compiled_arg = translator.translate(x)
+
+    return '%s%s%s(%s)' % (f_name, how, f_type, compiled_arg)
+
+
+@compiles(Corr)
+def compile_corr(translator, expr):
+    # pull out the arguments to the expression
+    args = expr.op().args
+
+    x, y = args
+
+    f_type = ''
+    if isinstance(x, ir.FloatingColumn) or isinstance(y, ir.FloatingColumn):
+        f_type = '_FLOAT'
+
+    # compile the argument
+    compiled_x = translator.translate(x)
+    compiled_y = translator.translate(y)
+
+    return 'CORR%s(%s, %s)' % (f_type, compiled_x, compiled_y)

ibis/mapd/identifiers.py

@@ -250,6 +250,7 @@
     'varchar',
 })
 
+# @TODO: check if it is necessary
 _ibis = frozenset({
     'literal'
 })

ibis/mapd/operations.py

@@ -12,6 +12,10 @@
 from ibis.expr.types import NumericValue, StringValue
 
 
+def pi_compile():
+    return 'pi()'
+
+
 def _cast(translator, expr):
     from ibis.mapd.client import MapDDataType
 
@@ -507,12 +511,15 @@ class Degrees(ops.UnaryOp):
     output_type = rlz.shape_like('arg', ops.dt.float)
 
 
-class PI(ops.Constant):
+class PI(ops.ValueOp):
     """Converts radians to degrees"""
     def output_type(self):
         return ops.dt.float64.scalar_type()
 
 
+pi = PI()
+
+
 class Log(ops.Ln):
     """
 
@@ -547,21 +554,21 @@ class Truncate(ops.NumericBinaryOp):
 
 # STATS
 """
-class Correlation(x, y)	CORRELATION_FLOAT(x, y)	Alias of CORR. Returns the coefficient of correlation of a set of number pairs.
-class  CORR(x, y)	CORR_FLOAT(x, y)	Returns the coefficient of correlation of a set of number pairs.
 class  COVAR_POP(x, y)	COVAR_POP_FLOAT(x, y)	Returns the population covariance of a set of number pairs.
 class  COVAR_SAMP(x, y)	COVAR_SAMP_FLOAT(x, y)	Returns the sample covariance of a set of number pairs.
-ops.StandardDev: agg_variance_like('stddev'),
-# STDDEV(x)	STDDEV_FLOAT(x)	Alias of STDDEV_SAMP. Returns sample standard deviation of the value.
-# STDDEV_POP(x)	STDDEV_POP_FLOAT(x)	Returns the population standard the standard deviation of the value.
-# STDDEV_SAMP(x)	STDDEV_SAMP_FLOAT(x)	Returns the sample standard deviation of the value.
-ops.Variance: agg_variance_like('var'),
-# VARIANCE(x)	VARIANCE_FLOAT(x)	Alias of VAR_SAMP. Returns the sample variance of the value.
-# VAR_POP(x)	VAR_POP_FLOAT(x)	Returns the population variance sample variance of the value.
-# VAR_SAMP(x)	VAR_SAMP_FLOAT(x)	Returns the sample variance of the value.
 """
 
 
+class Corr(ops.BinaryOp):
+    """
+    Returns the coefficient of correlation of a set of number pairs.
+
+    """
+    x = ops.Arg(rlz.numeric)
+    y = ops.Arg(rlz.numeric)
+    output_type = rlz.shape_like('x', ops.dt.float)
+
+
 # TRIGONOMETRY
 
 class TrigonometryUnary(ops.UnaryOp):
@@ -705,18 +712,11 @@ class StringLengthBytes(ops.UnaryOp):
 }
 
 _stats_ops = {
-    # CORRELATION(x, y)	CORRELATION_FLOAT(x, y)	Alias of CORR. Returns the coefficient of correlation of a set of number pairs.
-    # CORR(x, y)	CORR_FLOAT(x, y)	Returns the coefficient of correlation of a set of number pairs.
+    Corr: fixed_arity('corr', 2),
     # COVAR_POP(x, y)	COVAR_POP_FLOAT(x, y)	Returns the population covariance of a set of number pairs.
     # COVAR_SAMP(x, y)	COVAR_SAMP_FLOAT(x, y)	Returns the sample covariance of a set of number pairs.
     ops.StandardDev: agg_variance_like('stddev'),
-    # STDDEV(x)	STDDEV_FLOAT(x)	Alias of STDDEV_SAMP. Returns sample standard deviation of the value.
-    # STDDEV_POP(x)	STDDEV_POP_FLOAT(x)	Returns the population standard the standard deviation of the value.
-    # STDDEV_SAMP(x)	STDDEV_SAMP_FLOAT(x)	Returns the sample standard deviation of the value.
     ops.Variance: agg_variance_like('var'),
-    # VARIANCE(x)	VARIANCE_FLOAT(x)	Alias of VAR_SAMP. Returns the sample variance of the value.
-    # VAR_POP(x)	VAR_POP_FLOAT(x)	Returns the population variance sample variance of the value.
-    # VAR_SAMP(x)	VAR_SAMP_FLOAT(x)	Returns the sample variance of the value.
 }
 
 
@@ -824,14 +824,24 @@ class StringLengthBytes(ops.UnaryOp):
 
 
 def assign_function_to_dtype(dtype, function_ops: dict):
-    # generate trigonometric function for NumericValue class
+    """
+
+    :param dtype:
+    :param function_ops:
+    :return:
+    """
     for klass in function_ops.keys():
         # skip if the class is already in the ibis operations
         if klass in ops.__dict__.values():
             continue
 
         def f(_klass):
+            """
+            Return a lambda function that return to_expr() result from the
+            custom classes.
+            """
             return lambda *args: _klass(*args).to_expr()
+        # assign new function to the defined DataType
         setattr(
             dtype, klass.__name__.lower(), f(klass)
         )
@@ -840,4 +850,5 @@ def f(_klass):
 assign_function_to_dtype(NumericValue, _trigonometric_ops)
 assign_function_to_dtype(NumericValue, _math_ops)
 assign_function_to_dtype(StringValue, _string_ops)
-assign_function_to_dtype(NumericValue, _geometric_ops)
+assign_function_to_dtype(NumericValue, _geometric_ops)
+assign_function_to_dtype(NumericValue, _stats_ops)

ibis/mapd/udf.py

@@ -0,0 +1,5 @@
+"""
+User Defined Function
+
+@see http://docs.ibis-project.org/udf.html
+"""