Intrinsic Logical Operations

A LOGICAL or boolean expression returns a .TRUE. / .FALSE. result. The following are valid with LOGICAL operands,

• .NOT. -- monadic `negation'. .TRUE. if operand is .FALSE., for example, .NOT.(a .LT. b),
• .AND. -- logical `and'. .TRUE. if both operands are .TRUE.;
• .OR. -- logical `or'. .TRUE. if at least one operand is .TRUE.;
• .EQV. -- equivalence. .TRUE. if operands are the same;
• .NEQV. -- non-equivalence.. .TRUE. if operands are different.

for example,

   REAL :: a, b, x, y
   LOGICAL :: l1, l2
    ...
   l1 = (.NOT.(x.EQ.y.AND.a.EQ.b))
   l2 = (l1.EQV.((x.GT.a.OR.y.LT.b).NEQV.a.EQ.b))

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