Float exponentiation and logarithm instructions - MLH (#2968)

* Float exponentiation and logarithm instructions

* Corrections to instructions and tests

* Revamping Math Instructions

* Changed E Constant and modified compute max

* Formatting and Clippy Linting

* increased log computation allowance

Co-authored-by: Ronald Hood <ronald.hood@yale.edu>

libraries/math/src/instruction.rs

@@ -70,6 +70,25 @@ pub enum MathInstruction {
         /// The divisor
         divisor: f32,
     },
+
+    /// Exponentiate a float base by a power
+    ///
+    /// No accounts required for this instruction
+    F32Exponentiate {
+        /// The base
+        base: f32,
+        /// The exponent
+        exponent: f32,
+    },
+
+    /// Natural Log of a float
+    ///
+    /// No accounts required for this instruction
+    F32NaturalLog {
+        /// The argument
+        argument: f32,
+    },
+
     /// Don't do anything for comparison
     ///
     /// No accounts required for this instruction
@@ -87,7 +106,7 @@ pub fn precise_sqrt(radicand: u64) -> Instruction {
     }
 }
 
-/// Create SquareRoot instruction
+/// Create U64 SquareRoot instruction
 pub fn sqrt_u64(radicand: u64) -> Instruction {
     Instruction {
         program_id: id(),
@@ -98,7 +117,7 @@ pub fn sqrt_u64(radicand: u64) -> Instruction {
     }
 }
 
-/// Create SquareRoot instruction
+/// Create U128 SquareRoot instruction
 pub fn sqrt_u128(radicand: u128) -> Instruction {
     Instruction {
         program_id: id(),
@@ -109,7 +128,7 @@ pub fn sqrt_u128(radicand: u128) -> Instruction {
     }
 }
 
-/// Create PreciseSquareRoot instruction
+/// Create U64 Multiplication instruction
 pub fn u64_multiply(multiplicand: u64, multiplier: u64) -> Instruction {
     Instruction {
         program_id: id(),
@@ -123,7 +142,7 @@ pub fn u64_multiply(multiplicand: u64, multiplier: u64) -> Instruction {
     }
 }
 
-/// Create PreciseSquareRoot instruction
+/// Create U64 Division instruction
 pub fn u64_divide(dividend: u64, divisor: u64) -> Instruction {
     Instruction {
         program_id: id(),
@@ -134,7 +153,7 @@ pub fn u64_divide(dividend: u64, divisor: u64) -> Instruction {
     }
 }
 
-/// Create PreciseSquareRoot instruction
+/// Create F32 Multiplication instruction
 pub fn f32_multiply(multiplicand: f32, multiplier: f32) -> Instruction {
     Instruction {
         program_id: id(),
@@ -148,7 +167,7 @@ pub fn f32_multiply(multiplicand: f32, multiplier: f32) -> Instruction {
     }
 }
 
-/// Create PreciseSquareRoot instruction
+/// Create F32 Division instruction
 pub fn f32_divide(dividend: f32, divisor: f32) -> Instruction {
     Instruction {
         program_id: id(),
@@ -159,7 +178,29 @@ pub fn f32_divide(dividend: f32, divisor: f32) -> Instruction {
     }
 }
 
-/// Create PreciseSquareRoot instruction
+/// Create F32 Exponentiate instruction
+pub fn f32_exponentiate(base: f32, exponent: f32) -> Instruction {
+    Instruction {
+        program_id: id(),
+        accounts: vec![],
+        data: MathInstruction::F32Exponentiate { base, exponent }
+            .try_to_vec()
+            .unwrap(),
+    }
+}
+
+/// Create F32 Natural Log instruction
+pub fn f32_natural_log(argument: f32) -> Instruction {
+    Instruction {
+        program_id: id(),
+        accounts: vec![],
+        data: MathInstruction::F32NaturalLog { argument }
+            .try_to_vec()
+            .unwrap(),
+    }
+}
+
+/// Create Noop instruction
 pub fn noop() -> Instruction {
     Instruction {
         program_id: id(),
@@ -277,6 +318,35 @@ mod tests {
         assert_eq!(instruction.program_id, crate::id());
     }
 
+    #[test]
+    fn test_f32_exponentiate() {
+        let instruction = f32_exponentiate(f32::MAX, f32::MAX);
+        assert_eq!(0, instruction.accounts.len());
+        assert_eq!(
+            instruction.data,
+            MathInstruction::F32Exponentiate {
+                base: f32::MAX,
+                exponent: f32::MAX
+            }
+            .try_to_vec()
+            .unwrap()
+        );
+        assert_eq!(instruction.program_id, crate::id())
+    }
+
+    #[test]
+    fn test_f32_natural_log() {
+        let instruction = f32_natural_log(f32::MAX);
+        assert_eq!(0, instruction.accounts.len());
+        assert_eq!(
+            instruction.data,
+            MathInstruction::F32NaturalLog { argument: f32::MAX }
+                .try_to_vec()
+                .unwrap()
+        );
+        assert_eq!(instruction.program_id, crate::id())
+    }
+
     #[test]
     fn test_noop() {
         let instruction = noop();

libraries/math/src/processor.rs

@@ -33,6 +33,16 @@ fn f32_divide(dividend: f32, divisor: f32) -> f32 {
     dividend / divisor
 }
 
+#[inline(never)]
+fn f32_exponentiate(base: f32, exponent: f32) -> f32 {
+    base.powf(exponent)
+}
+
+#[inline(never)]
+fn f32_natural_log(argument: f32) -> f32 {
+    argument.ln()
+}
+
 /// Instruction processor
 pub fn process_instruction(
     _program_id: &Pubkey,
@@ -104,6 +114,22 @@ pub fn process_instruction(
             msg!("{}", result as u64);
             Ok(())
         }
+        MathInstruction::F32Exponentiate { base, exponent } => {
+            msg!("Calculating f32 Exponent");
+            sol_log_compute_units();
+            let result = f32_exponentiate(base, exponent);
+            sol_log_compute_units();
+            msg!("{}", result as u64);
+            Ok(())
+        }
+        MathInstruction::F32NaturalLog { argument } => {
+            msg!("Calculating f32 Natural Log");
+            sol_log_compute_units();
+            let result = f32_natural_log(argument);
+            sol_log_compute_units();
+            msg!("{}", result as u64);
+            Ok(())
+        }
         MathInstruction::Noop => {
             msg!("Do nothing");
             msg!("{}", 0_u64);
@@ -142,6 +168,24 @@ mod tests {
         assert_eq!(2.0, f32_divide(2.0, 1.0));
     }
 
+    #[test]
+    fn test_f32_exponentiate() {
+        assert_eq!(16.0, f32_exponentiate(4.0, 2.0));
+        assert_eq!(4.0, f32_exponentiate(16.0, 0.5))
+    }
+
+    #[test]
+    fn test_f32_natural_log() {
+        let one = 1.0f32;
+        // e^1
+        let e = one.exp();
+
+        // ln(e) - 1 == 0
+        let abs_difference = (f32_natural_log(e) - 1.0).abs();
+
+        assert!(abs_difference <= f32::EPSILON);
+    }
+
     #[test]
     fn test_process_instruction() {
         let program_id = Pubkey::new_unique();
@@ -167,6 +211,13 @@ mod tests {
                 dividend: 2.0,
                 divisor: 2.0,
             },
+            MathInstruction::F32Exponentiate {
+                base: 4.0,
+                exponent: 2.0,
+            },
+            MathInstruction::F32NaturalLog {
+                argument: std::f32::consts::E,
+            },
             MathInstruction::Noop,
         ] {
             let input = math_instruction.try_to_vec().unwrap();

libraries/math/tests/instruction_count.rs

@@ -147,6 +147,38 @@ async fn test_f32_divide() {
     banks_client.process_transaction(transaction).await.unwrap();
 }
 
+#[tokio::test]
+async fn test_f32_exponentiate() {
+    let mut pc = ProgramTest::new("spl_math", id(), processor!(process_instruction));
+
+    pc.set_compute_max_units(1400);
+
+    let (mut banks_client, payer, recent_blockhash) = pc.start().await;
+
+    let mut transaction = Transaction::new_with_payer(
+        &[instruction::f32_exponentiate(4_f32, 2_f32)],
+        Some(&payer.pubkey()),
+    );
+    transaction.sign(&[&payer], recent_blockhash);
+    banks_client.process_transaction(transaction).await.unwrap();
+}
+
+#[tokio::test]
+async fn test_f32_natural_log() {
+    let mut pc = ProgramTest::new("spl_math", id(), processor!(process_instruction));
+
+    pc.set_compute_max_units(3500);
+
+    let (mut banks_client, payer, recent_blockhash) = pc.start().await;
+
+    let mut transaction = Transaction::new_with_payer(
+        &[instruction::f32_natural_log(1_f32.exp())],
+        Some(&payer.pubkey()),
+    );
+    transaction.sign(&[&payer], recent_blockhash);
+    banks_client.process_transaction(transaction).await.unwrap();
+}
+
 #[tokio::test]
 async fn test_noop() {
     let mut pc = ProgramTest::new("spl_math", id(), processor!(process_instruction));